2025-06-14T03:35:00
permalink Post: 11901109
Ex petroleum lab technician and tank farm sampler here.
Jetstar Boeing 787-8 VH-VKJ General Electric GEnx-1B Engine Biocide Serious Incident near Kansai
On 29 March 2019 the No 1 General Electric GEnx-1B engine of Jetstar Airways Boeing 787-8 VH-VKJ , flying from Cairns , Australia to Osaka Kansai Internationa l, Japan, fell below idle during the descent at an altitude of about 16,000 ft for 8 seconds. The No 2 engine then fell below idle too for 81 seconds. The aircraft safely landed at Kansai International less than 30 minutes later.2025-06-14T04:00:00
permalink Post: 11901123
Ex petroleum lab technician and tank farm sampler here. We would occasionally get fuel samples from crashed aircraft to test for contamination. One test was for water and sediment/microorganism sludge.
In this accident, fuel contamination continues to be dismissed as a cause, because no other aircraft have reported issues. But there has been no discussion regarding the airport's fuel storage, transfer, or filtration systems. Water and sediment naturally settles at the bottom of fuel storage tanks. If this aircraft received fuel drawn from the bottom of a storage tank, in the absence of a proper filtration system, it\x92s possible that it was contaminated. The next aircraft may have received fuel from a different storage tank with good fuel.
In this accident, fuel contamination continues to be dismissed as a cause, because no other aircraft have reported issues. But there has been no discussion regarding the airport's fuel storage, transfer, or filtration systems. Water and sediment naturally settles at the bottom of fuel storage tanks. If this aircraft received fuel drawn from the bottom of a storage tank, in the absence of a proper filtration system, it\x92s possible that it was contaminated. The next aircraft may have received fuel from a different storage tank with good fuel.
Fuel contamination is certainly a valid theory. The main thing working against it is that it would seem from the aircraft's flight path is that both engines failed at exactly the same time and lost thrust simultaneously. The chances of this are non zero, but remote. I say that as there appears to be no yaw, or other controlling of the aircraft - either by pilot or automation - that would suggest an asymmetric thrust scenario, even for a few seconds.
Yes, Jetstar had the biocide issue but did not immediately hit both engines within seconds of each other.
It's my understanding that both engines draw fuel from independent sources during that time (which may be fed from a common source (eg central tank). But again, the odds of both failing at the exact same instant is low, but not zero.
2025-06-14T06:31:00
permalink Post: 11901163
Ex petroleum lab technician and tank farm sampler here. We would occasionally get fuel samples from crashed aircraft to test for contamination. One test was for water and sediment/microorganism sludge.
In this accident, fuel contamination continues to be dismissed as a cause, because no other aircraft have reported issues. But there has been no discussion regarding the airport's fuel storage, transfer, or filtration systems. Water and sediment naturally settles at the bottom of fuel storage tanks. If this aircraft received fuel drawn from the bottom of a storage tank, in the absence of a proper filtration system, it\x92s possible that it was contaminated. The next aircraft may have received fuel from a different storage tank with good fuel.
In this accident, fuel contamination continues to be dismissed as a cause, because no other aircraft have reported issues. But there has been no discussion regarding the airport's fuel storage, transfer, or filtration systems. Water and sediment naturally settles at the bottom of fuel storage tanks. If this aircraft received fuel drawn from the bottom of a storage tank, in the absence of a proper filtration system, it\x92s possible that it was contaminated. The next aircraft may have received fuel from a different storage tank with good fuel.
Also, for them to fail at exactly the same time with near full tanks (as evidenced from the explosion) doesn't give much credence to the contaminated fuel theory in my opinion.
2025-06-14T07:18:00
permalink Post: 11901188
A summary of the more certain things we know about the accident so far:
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.
14 users liked this post.
2025-06-14T07:44:00
permalink Post: 11901210
Sometimes complex sequences can have very simple causalities. A lot of complex speculation in this thread so far focused on highly technical things. Yet the basic fundamentals of powered flight have not changed (despite our attempts to do so) over the past 100 years.
Fact 1: The airplane stopped going up because it lacked excess thrust necessary to sustain the climb, and;
Fact 2: The airplane’s airspeed decreased constantly because they were trying to maintain either altitude or the climb, but lacked the thrust to do so, and;
Fact 3: If they had prematurely raised the flaps, the climb rate would have decreased/possibly turned negative, but the airplane would have continued to accelerate.
So where did the thrust go?
Fact 4: There is no adverse yaw seen in any of the videos, so wherever it went the loss of thrust occurred (nearly) simultaneously in both engines.
Fact 5: The only way to stop a jet engine from thrusting (sorry) is by either blowing it up or removing the fuel supply. If it blows up- like from birds trying to become a fuel source, there will be evidence. (See Jeju Air for a good example.)
Fact 6: There is (so far) no evidence of either engine blowing up. (I’m deliberately using highly technical terms here…)
Fact 7: There is unmistakably clear audible evidence of the RAT being deployed on the raw video from the right rear quarter of the airplane. Near supersonic propellor blades are an unmistakable sound- the RAT was definitively deployed no matter how much people want to argue to the contrary.
Fact 8: In the same video there is silence from the engines when they should be thundering at full (or nearly full) power. (Yes, I know that isn’t a thing- I am a simple man alas.)
Thus the only possible conclusions are (cringes as he waits for fdr to rip him a new ah):
There are a very finite number of possibilities to that answer- and I do have my suspicions, but I lack the qualification to opine on that one.
I’ll leave the rest to the more experienced folk here.
Warm regards-
dce
- As a general rule it is a bad idea to run out of either altitude or airspeed or both.
- If you try to maintain altitude without sufficient thrust you will eventually run out of airspeed.
- If you have sufficient thrust you can maintain your altitude at a given airspeed, and if you have excess thrust you can maintain your airspeed and increase your altitude. If you have lots of excess thrust you can increase your altitude and increase your airspeed.
- If you try to increase your altitude by pitching the nose up, and without sufficient excess thrust, your speed will decay quickly, up to the point of stall, at which point you will lose any small amount of altitude you have gained and begin descending.
Fact 1: The airplane stopped going up because it lacked excess thrust necessary to sustain the climb, and;
Fact 2: The airplane’s airspeed decreased constantly because they were trying to maintain either altitude or the climb, but lacked the thrust to do so, and;
Fact 3: If they had prematurely raised the flaps, the climb rate would have decreased/possibly turned negative, but the airplane would have continued to accelerate.
So where did the thrust go?
Fact 4: There is no adverse yaw seen in any of the videos, so wherever it went the loss of thrust occurred (nearly) simultaneously in both engines.
Fact 5: The only way to stop a jet engine from thrusting (sorry) is by either blowing it up or removing the fuel supply. If it blows up- like from birds trying to become a fuel source, there will be evidence. (See Jeju Air for a good example.)
Fact 6: There is (so far) no evidence of either engine blowing up. (I’m deliberately using highly technical terms here…)
Fact 7: There is unmistakably clear audible evidence of the RAT being deployed on the raw video from the right rear quarter of the airplane. Near supersonic propellor blades are an unmistakable sound- the RAT was definitively deployed no matter how much people want to argue to the contrary.
Fact 8: In the same video there is silence from the engines when they should be thundering at full (or nearly full) power. (Yes, I know that isn’t a thing- I am a simple man alas.)
Thus the only possible conclusions are (cringes as he waits for fdr to rip him a new ah):
- The engines stopped burning, at nearly the same moment in time.
- As a result, the airplane stopped climbing and also began to lose airspeed in an attempt to maintain altitude.
- The RAT being deployed so quickly means that the ‘puters believed both engines were dead donks. (They were.)
- If both engines ceased burning it meant the fuel supply was interrupted. We aren’t talking flight idle here- it was lights out for both.
- (I am quoting someone else here) There is enough suction for the fuel to feed even if the fuel pumps are inop.
- The engines stopped being provided with fuel. Because something physical was placed between the tanks and the burners. And they flamed out.
There are a very finite number of possibilities to that answer- and I do have my suspicions, but I lack the qualification to opine on that one.
I’ll leave the rest to the more experienced folk here.
Warm regards-
dce
27 users liked this post.
2025-06-14T07:51:00
permalink Post: 11901217
How is misselected flap still being discussed? Misselected flap does not cause gear retraction to cease nor cause the RAT to deploy. Both of which are (subjectively) evidenced in the videos. What is the supporting evidence for misselected flap?
Yes absolutely. 100% catastrophic loss of power when getting airborne. No evidence for bird strikes\x85no severe eng damage symptoms in the videos, no mention of birds in the mayday\x85
they\x92ve gone TO power all the way to rotate, no power issues, no eng fuel issues, but as soon as its wheels off they lose all power. That can\x92t be coincidental. TCMA certainly fits this scenario especially with ground/air logic.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else.
they\x92ve gone TO power all the way to rotate, no power issues, no eng fuel issues, but as soon as its wheels off they lose all power. That can\x92t be coincidental. TCMA certainly fits this scenario especially with ground/air logic.
1 user liked this post.
2025-06-14T08:30:00
permalink Post: 11901251
A summary of the more certain things we know about the accident so far:
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction. What exactly caused the engine/electrical issues remains speculative. An action slip mistaking flaps for gear seems much less likely as due to the above, the correct selection was probably made.
From the videos of the last moments, there is strong evidence that the RAT was deployed, which has a very short list of possible triggers. The sole eye witness from inside describes power issues which lends credence.
Taken together, it seems that there was an event (or events) shortly after rotation that compromised both engines and the electrical system. There is no evidence yet of birdstrikes and continued engine operation *should* not be affected by the aircraft electrical system as they are independently/internally powered, so logic would have the engines failing first leading to a cascade of other problems. Something that affects all engines pretty much simultaneously is a rare beast but it has happened in the past; outside of a deliberate selection of the fuel and/or fire switches for both power plants there is fuel contamination, FOD and not much else. Its seems at least one FDR has been recovered so depending on where they take it for read-out, we should get some initial facts fairly shortly.
This indeed is the best summary till now
3 users liked this post.
2025-06-14T08:38:00
permalink Post: 11901260
Sometimes complex sequences can have very simple causalities. A lot of complex speculation in this thread so far focused on highly technical things. Yet the basic fundamentals of powered flight have not changed (despite our attempts to do so) over the past 100 years.
Fact 1: The airplane stopped going up because it lacked excess thrust necessary to sustain the climb, and;
Fact 2: The airplane\x92s airspeed decreased constantly because they were trying to maintain either altitude or the climb, but lacked the thrust to do so, and;
Fact 3: If they had prematurely raised the flaps, the climb rate would have decreased/possibly turned negative, but the airplane would have continued to accelerate.
So where did the thrust go?
Fact 4: There is no adverse yaw seen in any of the videos, so wherever it went the loss of thrust occurred (nearly) simultaneously in both engines.
Fact 5: The only way to stop a jet engine from thrusting (sorry) is by either blowing it up or removing the fuel supply. If it blows up- like from birds trying to become a fuel source, there will be evidence. (See Jeju Air for a good example.)
Fact 6: There is (so far) no evidence of either engine blowing up. (I\x92m deliberately using highly technical terms here\x85)
Fact 7: There is unmistakably clear audible evidence of the RAT being deployed on the raw video from the right rear quarter of the airplane. Near supersonic propellor blades are an unmistakable sound- the RAT was definitively deployed no matter how much people want to argue to the contrary.
Fact 8: In the same video there is silence from the engines when they should be thundering at full (or nearly full) power. (Yes, I know that isn\x92t a thing- I am a simple man alas.)
Thus the only possible conclusions are (cringes as he waits for fdr to rip him a new ah):
There are a very finite number of possibilities to that answer- and I do have my suspicions, but I lack the qualification to opine on that one.
I\x92ll leave the rest to the more experienced folk here.
Warm regards-
dce
- As a general rule it is a bad idea to run out of either altitude or airspeed or both.
- If you try to maintain altitude without sufficient thrust you will eventually run out of airspeed.
- If you have sufficient thrust you can maintain your altitude at a given airspeed, and if you have excess thrust you can maintain your airspeed and increase your altitude. If you have lots of excess thrust you can increase your altitude and increase your airspeed.
- If you try to increase your altitude by pitching the nose up, and without sufficient excess thrust, your speed will decay quickly, up to the point of stall, at which point you will lose any small amount of altitude you have gained and begin descending.
Fact 1: The airplane stopped going up because it lacked excess thrust necessary to sustain the climb, and;
Fact 2: The airplane\x92s airspeed decreased constantly because they were trying to maintain either altitude or the climb, but lacked the thrust to do so, and;
Fact 3: If they had prematurely raised the flaps, the climb rate would have decreased/possibly turned negative, but the airplane would have continued to accelerate.
So where did the thrust go?
Fact 4: There is no adverse yaw seen in any of the videos, so wherever it went the loss of thrust occurred (nearly) simultaneously in both engines.
Fact 5: The only way to stop a jet engine from thrusting (sorry) is by either blowing it up or removing the fuel supply. If it blows up- like from birds trying to become a fuel source, there will be evidence. (See Jeju Air for a good example.)
Fact 6: There is (so far) no evidence of either engine blowing up. (I\x92m deliberately using highly technical terms here\x85)
Fact 7: There is unmistakably clear audible evidence of the RAT being deployed on the raw video from the right rear quarter of the airplane. Near supersonic propellor blades are an unmistakable sound- the RAT was definitively deployed no matter how much people want to argue to the contrary.
Fact 8: In the same video there is silence from the engines when they should be thundering at full (or nearly full) power. (Yes, I know that isn\x92t a thing- I am a simple man alas.)
Thus the only possible conclusions are (cringes as he waits for fdr to rip him a new ah):
- The engines stopped burning, at nearly the same moment in time.
- As a result, the airplane stopped climbing and also began to lose airspeed in an attempt to maintain altitude.
- The RAT being deployed so quickly means that the \x91puters believed both engines were dead donks. (They were.)
- If both engines ceased burning it meant the fuel supply was interrupted. We aren\x92t talking flight idle here- it was lights out for both.
- (I am quoting someone else here) There is enough suction for the fuel to feed even if the fuel pumps are inop.
- The engines stopped being provided with fuel. Because something physical was placed between the tanks and the burners. And they flamed out.
There are a very finite number of possibilities to that answer- and I do have my suspicions, but I lack the qualification to opine on that one.
I\x92ll leave the rest to the more experienced folk here.
Warm regards-
dce
The FMA\x92s will be:
THR REF | LNAV | VNAV SPD
1 user liked this post.
2025-06-14T08:43:00
permalink Post: 11901266
I’m not a 787 driver so for fear of looking dumb in front of those that are this still confuses me. Even IF they’ve mis-selected the flap setting (I still don’t think it’s been cemented on here that there is in fact a FMS/flap setting disagreement warning but i believe there is), had the wrong de-rated take off settings, selected flaps instead of gear up the 787 with massive high bypass engines, FBW and full envelope protections surely cannot let itself be put in such a low energy/high alpha regime as we saw in the videos IF it has both fans functioning normally, surely?
the pilots may have messed up royally and numerous times so those holes lined up but the plane is the final block in the chain and a 21st century all digital entirely clean sheet design was sold as being immune to such catastrophic outcomes from a few minor (consequential yes) and fairly common errors- aren’t all the protections and our procedures designed after decades of mistakes?
im having a hard time squaring how a fully functioning modern bird like this could allow for this outcome and almost whatever the pilots did outside of unbelievable inputs and the pilots are are a bit of a red herring IMO
Dale Winsley
@Winsleydale
No. The LE slats are deployed therefore the flaps are as well. This is an automatic linkage. The flaps are set at Take-Off. Hard to see from the angle but they are...if slats are out (easy to see) then flaps are set. Looks like Flaps 5. Also, the 787 has the highest Thrust-to-Weight ratio of any airliner on Earth. The change in Alpha and lift is a trifling matter for it, at these settings (1-5). It will fly out of it easily, even at that density altitude. The attitude change is - in the circumstances I describe, consistent with a massive power loss (both sides). I believe based on probability that simultaneous mechanical failure is not the cause. Fuel contamination or starvation is likewise unlikely based on the 787 fuel system. The common element is the FADEC/Autothrottle/TOGO. However, each engine FADEC is dual redundant two channels. So any such common failure must happen further upstream. From a design perspective, that would be unthinkable. But this is Boeing. Given what I can see with my own eyes, I believe the flap issue is a non-starter. Also, re the landing gear: Clearly the Positive Rate challenge would be met based on normal rotation and fly-off at V2. But since we know the flaps were set correctly, that rules out an "oopsie" moment. Just as likely there was at the challenge moment an indication that something was amiss, and the Gear Up call was not made. They see both N1s unwinding and it takes a second to get past the WFT factor. They cross-check and see the airspeed also unwinding. Then they unload the Alpha and pitch to gear down Vy. And they had another 6 seconds. Whatever it was, it was not a flap, mechanical or fuel issue. We will know soon enough. But this is Boeing. My gut says "software". All 787s worldwide need to be grounded, now.
6:10 AM \xb7 Jun 14, 2025
\xb7
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Last edited by Senior Pilot; 14th Jun 2025 at 09:04 . Reason: Add X quote
2025-06-14T09:20:00
permalink Post: 11901298
If this is correct, does it point more towards the engines having been erroneously shut down earlier, rather than a fuel starvation or contamination issue?
2 users liked this post.
2025-06-14T09:23:00
permalink Post: 11901300
Double power loss causality
A summary of the more certain things we know about the accident so far:
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction .
The takeoff run was from the full length and appeared normal, even after comparing with the same flight on previous days. This very much reduces the likelihood of it being a performance issue, e.g. wrong flaps, derate, ZFW/TOW, etc.
Shortly after takeoff, the gear started retracting but stopped in an early intermediate position. At the same time the aircraft climb rate dropped off, then it started a shallow descent. This is consistent with a loss of electrical power causing a loss of hydraulic pressure and total engine thrust from both engines reducing below that generated by one engine at the takeoff setting. The position reporting also went offline at that moment, indicating that it was likely load shed due to an electrical malfunction .
I personally think this is a good summary of what we can ascertain at this point from the evidence we have.
I am not a 787 driver by any means but with a fair bit of aviation experience. I would be interested in any thoughts on this suggestion regarding loss of thrust:
If we take it as a reasonable assumption as above that it is almost simultaneous loss of significant thrust, and for the good reasons already discussed, it is pretty unlikely that from what we can see/analyse, that the cause of this would be bird strike (expect to see some signs on video if it's significant enough to cause double engine failure) nor fuel contamination (reasons as above re: likelihood, other ac affected and simultaneous nature). TCMA I don't know enough about but it seems that the sensor redundancy/logic protection is so high it would not be the sole cause.
On this basis, should we perhaps consider the causality of a total electrics failure of some kind first, leading to deployment of the RAT, gear retraction cease etc. Clearly the independent FADEC power generation systems would mean this doesn't on its own prevent thrust control of the engines but could we then be looking at cascading faults (possibly exacerbated by latent faults below the MEL/defect threshold) that contribute to dual power loss and sensor/system issues in throttle response not resulting in FADEC commands to the engines to increase thrust. So even at that point 'firewalling' the throttles could tragically not recover the situation?
Very happy to be corrected by those with much more experience and understanding of big jets operations and systems!
2025-06-14T11:48:00
permalink Post: 11901396
Having looked at the photos of the wings, one wing appears to have flaps and slats, the other does not.
this could be from post impact damage, but an interesting observation.
From what I can see so far, there is an electrical event that occurs.
but why and how that causes an aircraft to crash, is to be determined.
This is either going to be a very quick or very long investigation, no in-between.
My gut instinct is this is going to be a previously unexpected or unplanned failure that, whilst there was redundancy (expected) it took it all out.
although a totally unrelated incident, it reminds me of the LHR 777 with the fuel pump heaters being designed to stop ice getting into the lines. But on that exact day, conditions and variables, the very system designed to mitigate said problems, became the problem.
this could be from post impact damage, but an interesting observation.
From what I can see so far, there is an electrical event that occurs.
but why and how that causes an aircraft to crash, is to be determined.
This is either going to be a very quick or very long investigation, no in-between.
My gut instinct is this is going to be a previously unexpected or unplanned failure that, whilst there was redundancy (expected) it took it all out.
although a totally unrelated incident, it reminds me of the LHR 777 with the fuel pump heaters being designed to stop ice getting into the lines. But on that exact day, conditions and variables, the very system designed to mitigate said problems, became the problem.
2025-06-14T12:04:00
permalink Post: 11901413
My next question, again I believe not discussed, is what do the 787 Fuel Cutoff switches actually do? Obviously, they cut off the fuel supplies to the engines - pretty important in engine fire and other scenarios, but goes without saying. The real question is, what do they activate (or deactivate)? I'm assuming a simple solenoid valve, which is open when powered and closed when unpowered, but of course, there will (certainly) be Electro-Mechanical or Solid-State (Electronic) relays between the switches and the (solenoid valves).
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
3 users liked this post.
2025-06-14T12:43:00
permalink Post: 11901451
Even though there is no point speculating about the cause of this accident, it is the nature of the beast to have questions. As pilots (most of us at least), we do have an inquiring mindset.
My initial thoughts were an inadvertent flap retraction. But with the ‘evidence’ that has been presented over the last 48 hours, I think we can safely discard that option.
What we think we know is:
- RAT was deployed (highly possible)
- Gear was selected up, but did not operate (bogey tilted, doors remained closed)
- APU was ‘on’ (APU door open on after crash pictures)
- Flight path
Any of these observations, alone, would mean very little. However, in combination, they all point to a dual engine flameout just at/after the rotation. The aircaft has enough kinetic energy to reach roughly 150ft altitude, end then starts a shallow descent at ‘alpha max’ into the buildings ahead. The RAT deployed, APU attempted auto-start, gear was unable to retract.
I only wonder why the engines spooled down. Bird strike seems to be out of the question, so that leaves us with only a very few options, which include a software bug or a suicidal pilot (not a popular option, I understand, but we have to take all options into account).
What I don’t believe is incorrect FCU selections, since that would not explain the high AOA on impact. It also would not explain the RAT, no gear retraction or the APU inlet flap open. Another thing that is highly unlikely is any switching done by the pilots, especially RAT etc.. These airborne time is just too little, pilots usually don’t take any action below approximately 400ft, and these switches are so ‘underused’ that a pilot would not find them instantaneously in a high stress situation.
For me, a dual engine flameout seems the only possible explanation, now we only have to wait for its cause.
My initial thoughts were an inadvertent flap retraction. But with the ‘evidence’ that has been presented over the last 48 hours, I think we can safely discard that option.
What we think we know is:
- RAT was deployed (highly possible)
- Gear was selected up, but did not operate (bogey tilted, doors remained closed)
- APU was ‘on’ (APU door open on after crash pictures)
- Flight path
Any of these observations, alone, would mean very little. However, in combination, they all point to a dual engine flameout just at/after the rotation. The aircaft has enough kinetic energy to reach roughly 150ft altitude, end then starts a shallow descent at ‘alpha max’ into the buildings ahead. The RAT deployed, APU attempted auto-start, gear was unable to retract.
I only wonder why the engines spooled down. Bird strike seems to be out of the question, so that leaves us with only a very few options, which include a software bug or a suicidal pilot (not a popular option, I understand, but we have to take all options into account).
What I don’t believe is incorrect FCU selections, since that would not explain the high AOA on impact. It also would not explain the RAT, no gear retraction or the APU inlet flap open. Another thing that is highly unlikely is any switching done by the pilots, especially RAT etc.. These airborne time is just too little, pilots usually don’t take any action below approximately 400ft, and these switches are so ‘underused’ that a pilot would not find them instantaneously in a high stress situation.
For me, a dual engine flameout seems the only possible explanation, now we only have to wait for its cause.
Last edited by Senior Pilot; 14th Jun 2025 at 19:08 . Reason: Double posting of image
2025-06-14T12:56:00
permalink Post: 11901460
I asked this yesterday, and was told no. You have to pull them out before you can move them up or down. So you can't operate them if, say, your hand slips violently off the throttle lever and drops down into the switches.
3 users liked this post.
2025-06-14T13:07:00
permalink Post: 11901468
This crash reminds me of the crash of a 747 Military Transport plane at an airbase in Afghanistan.
Shortly after TO, the cargo shifted, the plane became very tail heavy and stalled a few hundred feet in the air. It was the weirdest sight. For what seems a few seconds, the plane just seemed to hang there, presumably on engine thrust.
In this crash, the problem also seems to occur soon after rotation, as if something inside moved in response to its change in attitude. Maybe a loose connection on a main bus cable that moved... Maybe only a millimetre. Or a tool left inside an electrical cabinet slid somewhere it shouldn't. The possibilities are numerous, and without a lot more information, there's no way to know what caused this. I suspect a major electrical fault, probably intermittent.
How long would it take to restart those engines after a Fuel Cutoff flame out? Is that what happened, just before impact?
Shortly after TO, the cargo shifted, the plane became very tail heavy and stalled a few hundred feet in the air. It was the weirdest sight. For what seems a few seconds, the plane just seemed to hang there, presumably on engine thrust.
In this crash, the problem also seems to occur soon after rotation, as if something inside moved in response to its change in attitude. Maybe a loose connection on a main bus cable that moved... Maybe only a millimetre. Or a tool left inside an electrical cabinet slid somewhere it shouldn't. The possibilities are numerous, and without a lot more information, there's no way to know what caused this. I suspect a major electrical fault, probably intermittent.
How long would it take to restart those engines after a Fuel Cutoff flame out? Is that what happened, just before impact?
2025-06-14T13:40:00
permalink Post: 11901495
Fuel cutoff switches
My next question, again I believe not discussed, is what do the 787 Fuel Cutoff switches actually do? Obviously, they cut off the fuel supplies to the engines - pretty important in engine fire and other scenarios, but goes without saying. The real question is, what do they activate (or deactivate)? I'm assuming a simple solenoid valve, which is open when powered and closed when unpowered, but of course, there will (certainly) be Electro-Mechanical or Solid-State (Electronic) relays between the switches and the (solenoid valves).
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
I guess the next obvious question is, is there anything else that can turn off those Fuel Cutoff Valves - a computer condition for example. I'm assuming not, but I think it needs to be considered.
Taking each switch individually, next, since this is part of an electrical circuit, and of necessity must include Electrical Relays, there is certainly at least one and in all probability two electric Power Sources involved in this circuit. One supply which passes through the switch to activate the relay, and, I'm assuming, a second, higher current and probably higher voltage supply which drives the (solenoid?) valve.
As I see it, interrupting either supply will have the same effect - if the system is wired in the Positive-Postive sense, meaning a current through the switch causes the relay to pass a current through the (solenoid). If either of these supplies is cut, the Fuel Shutoffs will shut off the fuel. So, the question is, where do these supplies come from, and under what circumstances could they be cut off?
Sure, it looks to some (myself included) like a near simultaneous cutoff of both engines, but that doesn't have to have been caused by either of the pilots. I know there is huge redundancy built into the 787 Electrical Systems, but some of the evidence is suggesting that there was something not right with the plane's electrical system. I'm also fairly sure that there will be parts and places where certain faults can take the system down, despite the redundancy. I can't say where, but it's very difficult to design a perfect system, especially where there has to be transfers between multiple potential supplies and single actuators, motors or valves.
Having spent years repairing electrical and electronic systems, I know that the most difficult of all electrical faults are the intermittent ones. And I suspect that this is at the root of this crash. An intermittent or faulty AOA sensor has "caused" (provoked) multiple famous crashes... Can't find the one I'm looking for (pre-1980, I think) as the Max AOA issues dominate.
I can cite a very personal example, which involved the electrical supply to my house. I had several computers running 24x365 so of course, ran them off a UPS, which turned out to be a very good thing. I started to notice that at certain times, the UPS would activate - it would cut in and take over the computer loads, its alarm would go off to indicate a power fault. But the power was still on! This carried on for weeks and I initially blamed the UPS. Then, I noticed that it only happened on very hot afternoons... Long story short, the fault was caused by an electrical linesman, probably 30 years earlier, failing to tighten up a joint clamp on the phase wire to our house, across the street. Heating caused expansion then movement, and the power would momentarily go off then back on, and the UPS detected this. I note that this crash was on a hot day, and maybe this plane (which I believe was repositioned for the flight), had not been operating in such high temperatures recently, meaning the problem went unnoticed.
2 users liked this post.
2025-06-14T13:43:00
permalink Post: 11901499
Reports coming in that Indian regulator has sent out a note for inspection of all GenX engines on the 787
2025-06-14T14:04:00
permalink Post: 11901512
A question for B787 pilots or mechanics.
Is it correct to assume that the EFSOV valves are actuated by the fuel flow and controlled by an electric signal coming directly from the relevant EEC. Meaning that the simultaneous closing of the 2 valves would require an improbable simultaneous failure of the 2 EEC, or that the 2 fuel switches are flipped from "run" to "cut-off" at almost the same time, feeding the same command to the 2 EEC.
And that the spar fuel valves are electrically actuated with the power coming from the hot battery bus and the signal coming from the aft electronic bay (possibly from the same control unit)?
(Note: not pretending to be a commercial pilot; just IR rated PPL).
Is it correct to assume that the EFSOV valves are actuated by the fuel flow and controlled by an electric signal coming directly from the relevant EEC. Meaning that the simultaneous closing of the 2 valves would require an improbable simultaneous failure of the 2 EEC, or that the 2 fuel switches are flipped from "run" to "cut-off" at almost the same time, feeding the same command to the 2 EEC.
And that the spar fuel valves are electrically actuated with the power coming from the hot battery bus and the signal coming from the aft electronic bay (possibly from the same control unit)?
(Note: not pretending to be a commercial pilot; just IR rated PPL).
1 user liked this post.
2025-06-14T14:09:00
permalink Post: 11901517
Max EGzt and autorelight
Combining all the bits and pieces of info from this thread so far, IMO we can theoretically sequence it thus using the video from the left:
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
00:18 Rotation. Normal takeoff config.
00:24 Gear up starts. per Raffael with FF.
......... FR24 ADSB last transmission (71ft, 172kt) just before runway threshold. Matches with video aircraft altitude at 1/2 wingspan.
......... ? Full power flameout leaves N2 ~ 60%; Airspeed < 200k so N2 will decay to 15% in 8-10s?
......... ? Takeoff EGT of 900C needs 25-35s to fall below 250C ?
00:27 Gear up stops. per Raffael with FF. Bogies tilted.
......... ? APU starts. 20-55s to 95%N?
......... Per 787 dual-engine fail/stall memory items, PM initiates Fuel Cutoff and Run.
00:28 Visible loss of thrust. Alt ~ 200ft using aircraft wingspan as measure.
......... Matches with eyewitness "within 5-10s ... it was stuck in the air".
......... Per 787 dual-engine fail/stall memory items, PM initiates RAT Switch for 1s. Whether auto or manual, the RAT initiates.
......... RAT "bang" heard by survivor
......... RAT coming online accounts for eyewitness "lights started flickering green and white".
......... Per 787 QRH below 1000ft, PF makes no change to Main Landing Gear and flaps, aircraft pointed straight for best glide.
00:31 Descending visibly, somewhere beyond the runway threshold. Alt ~ 200ft using aircraft wingspan as measure.
......... ? Because EGT > 250C FADEC blocks fuel (T-HOT hot restart inhibit?) so no relight though N2 > 15% ?
......... 787 glide ratio between 16:1 to 25:1 with MLG down, Flaps 5. About 15-20s and 3-5000ft of glide from 200ft?
......... Some flap accounts for the ground pictures.
00:34 ? N2 has presumably decayed to 15%, FADEC flips to X-START: airspeed outside envelope? No hope of relight now.
......... PM/PF transmits Mayday?
......... Video showing RAT deployed.
00:46 APU reaches some fraction of 95%N (APU sound accounting for survivor's perception of thrust?).
00:48 Impact. 4200ft from descent start, 3990ft from airport boundary road. 17s from visible descent start.
if this is a valid sequence, the only remaining question is why the dual-engine failure at ~200ft agl?
with condolences to the families and people affected.
In-flight, the Autorelight function should attempt to restart the engine as soon as a flameout is detected, and for an engine flaming out at high power it might catch it before it even goes sub-idle. Generally, Autorelight will continue attempting until some cutoff N2 at which time it will stop attempting, or if the pilot move the fuel switch to Cutoff. And while the EEC is still powered (via its own PMA) down to roughly 10% N2, the ignition exciters required for Autorelight do get their power from the airplane.