Posts by user "Sailvi767" [Posts: 57 Total up-votes: 0 Pages: 3]

Sailvi767
July 01, 2025, 12:39:00 GMT
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Post: 11914246
Originally Posted by TURIN
May I ask where this information of load shedding comes from please
In my experience the APU supplies enough power to run all systems. Hydraulic pumps, fuel pumps etc
On the 767, 757 and A330 anytime you are in single generator operations the aircraft is load shedding. The 787 with a totally different electrical system might function differently.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): APU  Fuel (All)  Generators/Alternators  Hydraulic Failure (All)

Sailvi767
July 01, 2025, 13:23:00 GMT
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Post: 11914271
Originally Posted by MaybeItIs
Sorry, you missed the point I was trying to make. \xa7 25.903(b) does say that the fuel system must be able to operate in an isolated, two-sided mode (for a twin engined jet), such that nothing on one side, such as bad fuel, will adversely affect the other engine. Of course, during Takeoff, both sides drawing fuel from a Centre Tank containing a lot of contaminants (e.g. Fuel Bug matter, water) is a scenario that could bring down the plane. We are all aware of that. But the point I was trying to make is that although \xa7 25.903(b) requires "at least one configuration" that separates both systems entirely (such as Left engine drawing from Left Main Tank, and Right from Right) which can be configured, the Rule doesn't appear to make that compulsory for Takeoff.

A lot of other posters here have stated that according to FCOM instructions, the normal, accepted 787 Takeoff configuration is "Both sides draw from centre" if the Centre tanks have enough fuel in them. I think (maybe wrongly) that this (prior few posts) is the first time this exact point has been raised. I hope I'm correct there. If not, my humble apologies.

The great thing about this forum and sadly, this tragic accident, is that it's drawing a few previously little-known worms out of the woodwork.
Considering that 99.8% of the time modern transports aircraft are single point refueled I am not sure why all the discussion about burning fuel out of one tank. If bad fuel was pumped it\x92s in all the tanks. Even on the A330 while each engine is fed from its respective inner tank the center tank fuel is pushed to both inner tanks. Contamination of the center tank would put contaminated fuel in both inner tanks.

\x93Fuel from the center tank is transferred to the inner tanks to keep the inner tanks near full. The FCMC automatically controls the flow from the center to the inner tanks by operating the inner tank inlet valves. The center tank pumps run continuously when there is fuel in the center tank and provide fuel to the fueling manifold. When the inner tanks are full, the inner tank inlet valves are commanded closed until the inner tank fuel is burned down to approximately 4400 lbs below full. At that point, the inner tank inlet valves reopen to allow the inner tanks to fill, and repeat. \x93

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Centre Tank  FCOM

Sailvi767
July 10, 2025, 11:12:00 GMT
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Post: 11918942
The data recorder has all the information most are questioning. They already know if the fuel control switches were selected to cutoff and they know if this happened before or after the loss of thrust. Perhaps the sequence of events will be more clear tomorrow. I can tell you that from aircraft rotation to loss of thrust was a very short time period. Perhaps 8 seconds. I simply won’t believe in that time period the crew were taking any non deliberate actions that would have shut the motors down.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All)  Fuel Cutoff Switches

Sailvi767
July 12, 2025, 11:42:00 GMT
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Post: 11920553
Originally Posted by vilas
RAT doesn't help retracting the gear. Full conversation hasn't come out. First thing should have been positive rate but it appears engines started winding down as they got airborne so attention shifted to engines.
The fuel control switches were moved to the off position approximately 3 seconds after weight off wheels.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All)  Fuel Cutoff Switches  RAT (All)

Sailvi767
July 12, 2025, 11:46:00 GMT
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Post: 11920554
Originally Posted by Musician
Was the RAT deployed manually?
The report says,
As per the EAFR data both engines N2 values passed below minimum idle speed, and the RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC.
This was 5 seconds after the fuel was cut off.

It suggests to me that the RAT deployment was initiated while the engines were still above idle and generating electrical power. Obviously one of the pilots could have done it via depressing the switch, as it's a "dual engine failure/stall" memory item (see Air India Ahmedabad accident 12th June 2025 Part 2 ) that won't hurt anything.

Is there a way for the RAT to deploy while the engines are still above idle?
Loss of hydraulics or electrics will auto deploy the rat. The timing to me however seems to match up with when the engines were selected off.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): EAFR  Fuel (All)  Fuel Cutoff  Fuel Cutoff Switches  Hydraulic Failure (All)  RAT (All)  RAT (Deployment)

Sailvi767
July 12, 2025, 11:50:00 GMT
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Post: 11920557
Originally Posted by AfricanSkies
10 seconds to respond is a long long time if you’ve just made a silly mistake, you’d have those switches back on in a second. The startle factor isn’t really a factor here, because you know what just happened.
What is also unusual to me is the 4 second gap between moving Eng 1 fuel switch from cutoff to run, and moving Eng 2 fuel switch from cutoff to run.

One would imagine that in this situation, speed of response would have been critical. Why the slow, deliberate ‘reaction’?
If the shutdown was intentional there likely would be a struggle to restore the switches.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All)  Fuel Cutoff Switches

Sailvi767
July 12, 2025, 20:28:00 GMT
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Post: 11920815
Originally Posted by jimtx
They don't have to be positively lifted if the detent rounded out due to wear or if the switch installed was one that the SAIB referenced with the locking feature disengaged. I can't discern a raised boss on the body of the left switch in Fig.13, page 10 of the AAIB report. I assume those switches have some internal over center locking mechanism also besides the spring on the lever that would not be needed if there was no detent. I do remember writing up a 767 switch a long time ago when the Captain noticed the detent was worn and he could shut down without lifting.
It’s very easy to tell if the switch is wearing or defective. It’s also the norm for everyone operating the switches to give them a tug to insure they are in the detents. It’s simply inconceivable that both switches failed in exactly the same way at almost exactly the same time and no pilot who flew the aircraft in the last year or so noticed the issues. Add to that the CVR statement and it’s beyond inconceivable.
On the other hand pilots deciding to end their lives in a spectacular fashion is not inconceivable. In fact over the last 25 years it may be the single most numerous reason for a catastrophic loss of a transport category aircraft operated at a major airline.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AAIB (All)  CVR  Fuel (All)  Fuel Cutoff Switches  Fuel Cutoff Switches (detent)  Special Airworthiness Information Bulletin

Sailvi767
July 12, 2025, 21:43:00 GMT
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Post: 11920859
Originally Posted by JPI33600
I beg to differ: not from a pilot's point of view who didn't read the bulletin. Please see below about the recommended "tug".

Not a pilot, but electronics engineer here: I finally understood what's wrong with the "defective" switches: on such a switch, if you raise it up (to change its position) and you turn it slightly clockwise or counterclockwise before releasing it, it will operate normally, but the detents are now "crossing" the lock tab, and this one doesn't prevent a move-it-without-raising-it-first action anymore. As far as I can tell from the position of the switches, you have to extend your arm sideways and put some effort in your wrist to activate these switches: chances are that such a movement results in some amount of rotation.



Agreed, but this "test" won't tell you if the detents are aligned or misaligned with the lock tab.



If both switches are "defective" ones (remember, that doesn't mean they don't do their job, only that some specific action may put them in a state where protection against unwanted action is lost), the same action from the same pilot may well put both switches in the dangerous configuration.

By the way, I find that the "check" recommended in the bulletin for a switch suspected from being "defective" is incredibly misleading. It will possibly detect a switch where the cap has already been turned, resulting in a misalignment of the lock tab with the detents, but it won't detect a switch waiting for a turn to put it in the dangerous configuration. The "check" should be "pull on the cap to raise it, try to turn it clockwise or counterclockwise while raised: if it can be turned, it's defective".



On the contrary, according to the above scenario, anything interacting with the switches (which are close to each other) can move them unexpectedly (the "iPhone falling" case), and the CVR statement would reflect the surprise of a pilot who actually didn't do anything wrong.

May I add that I consider the probability of such a scenario as very very thin, but I wanted to emphasize the fact that we must keep our minds open, instead of jumping to conclusions too early.
In 25,000 hours I have never seen anything left on the glare shield or anywhere else during takeoff that could effect the switches. I have move those switches hundreds and hundreds of times. The one time there was an issue it was apparent quite readily. Not only do the switches have their own internal locking mechanism they also have guards on either side. I can\x92t conceive of how something could fall so precisely as to miss the guards and impact both switches causing a simo shutdown. If that did happen you would also expect it to occur at rotation not 5 seconds later.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR  Fuel (All)  Fuel Cutoff Switches  Fuel Cutoff Switches (detent)  Switch Guards

Sailvi767
July 13, 2025, 02:20:00 GMT
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Post: 11920987
Originally Posted by Alty7x7
My recollection is that the fire handle will be locked in this circumstance, unless the respective fuel control switch is at Cutoff. Engine fire procedure (and not before 400 ft AGL) is fuel control switch to Cutoff and then pull the fire handle (turn left for bottle 1, turn right for bottle 2).
There is a lock release on the fire handles.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Fuel (All)  Fuel Cutoff Switches

Sailvi767
July 13, 2025, 10:36:00 GMT
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Post: 11921215
Originally Posted by Herc708
Does the EAFR record the electrical / physical contact of the RUN / CUTOFF switch or, does it record a software 'EVENT' which has the same 'signature' as the RUN / CUTOFF switch being toggled. My thoughts are that the RUN / CUTOFF switch never moved but, the underlying software / hardware system mal-functioned triggering a scenario similar to both RUN / CUTOFF switches being triggered

Some Boeing SB's describe circuit board failures triggering all sorts of unexpected / unpredictable failures
So the board affected all the functions of both switches simultaneously and then restored all functions on both sides about 10 seconds later? I find that just as unlikely as the constant posts about a A350 suffering a single engine shutdown due to a liquid spill. For those advocating the liquid theory please take a close look at how the fuel control switches are mounted by Boeing verses Airbus. The Airbus design is very vulnerable to a liquid spill. The Boeing design by virtue of where and how it’s mounted is not.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): EAFR  Engine Failure (All)  Engine Shutdown  Fuel (All)  Fuel Cutoff Switches  RUN/CUTOFF

Sailvi767
July 14, 2025, 11:20:00 GMT
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Post: 11922099
Originally Posted by Tailspin Turtle
From the beginning, my impression looking at the final glide video was that they weren't sinking as fast as I would have expected with both engines failed completely. A rough analysis using 787 L/D data, revisited as more speed and altitude estimates became available, convinced me that it was very unlikely that they could have gotten that far in that configuration with not only no thrust, but the drag from that big windmilling front fan on each engine. The preliminary report states they got at least one engine turning, apparently fast enough to reduce that drag and therefore get them to the crash site. However, as tdracer opined, a few more seconds would not have allowed for enough thrust to develop to stop the descent before ground contact.
One engine started to accelerate from the minimum speed reached. While that may have reduced drag very slightly I doubt it changed the impact point of the aircraft more than a few meters. The time from cutoff to run on the number 1 engine was 19 seconds before impact.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Engine Failure (All)  Engine Shutdown  Fuel (All)  Fuel Cutoff Switches  Preliminary Report

Sailvi767
July 15, 2025, 01:45:00 GMT
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Post: 11922617
There is no way any pilot would be touching the stab trim switches right after rotation. It would go against every aspect of training. If the aircraft is flying ok you would never touch anything trim related until after cleanup and working the appropriate QRH or EICAS. I know some will bring up the Delta flight at LAX however that occurred above a 1000 feet and was in compliance with company policy and Boeing at the time where you got one free punch to reset the EEC.
It would also have been a data point on the FDR and in the preliminary report.


Subjects (links are to this post in the relevant subject page so that this post can be seen in context): EICAS  FDR  Preliminary Report

Sailvi767
July 15, 2025, 12:11:00 GMT
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Post: 11922878
Originally Posted by AirScotia
Given the engines roaring, headphones etc. - would it have been possible for the PF to hear the switches being clicked?
Doubtful depending on his headset. The engines however don\x92t roar in the cockpit. You would however almost certainly see hand movement through peripheral vision and interpret that as non normal. The trust levers and cutoffs are forward of the seating position.

Subjects: None

Sailvi767
July 15, 2025, 22:04:00 GMT
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Post: 11923302
Originally Posted by AirScotia
So why did they give so much space to a discussion of SAIB NM-18-33? It's obvious that the switches were not faulty, or they'd have said. If they couldn't tell if the switches were faulty, they'd have said. They do tell us that the throttle control module was swapped out and there's been no problem with the switches. So they don't need to mention it. It doesn't read to me as a logical part of the preliminary report, but as something they were under pressure to include to imply that there may have been a technical problem rather than pilot malfunction.
The issue received extensive news coverage. I am sure they felt a need to address it.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Preliminary Report  SAIB NM-18-33  Special Airworthiness Information Bulletin

Sailvi767
July 17, 2025, 12:02:00 GMT
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Post: 11924345
Originally Posted by OhForSure
I have not posted on here in many years, but I feel compelled to do so now. I am a current 787 pilot and I have previously flown most Boeing types and an Airbus too. I also have an extensive background and qualifications in human factors, training and assessment. Before anybody reads any further, perhaps acquaint yourself with the notion of Occam's razor. That is, the simplest explanation is the most likely explanation. I was certain that after the preliminary report was released the preposterous conspiracy theories would finally cease, but no! It's 2025 and humans can no longer help themselves. In my opinion the captain committed suicide here. Simple.

To those suggesting an electrical phantom turned the fuel control switches off without them moving: no. Ask yourselves this: what made one pilot (PF and F/O in my opinion) ask the other "why did you cut off?" Firstly, some context. The 787 fuel control switches make a VERY distinct metallic *CLICK* sound as they are operated. EVERY 787 pilot knows it and won't forget it. It is audible even at high thrust settings owing to the 787's exceptionally quiet engines and cockpit. After rotation the pilot flying is fixated on the HUD; rotating towards the TOGA reference line (~12 degrees pitch attitude) and putting the flight path vector over the flight guidance cue. One hand would be on the control column and the other on the thrust levers. Alternatively he could have had both hands on the control column. In either scenario, the pilot flying's (again, my opinion the F/O's) inboard arm would block his peripheral view (he's focused on the HUD, remember) of the center pedestal and the fuel control switches. HE WOULD NOT SEE THE PM TURN THE FUEL CONTROL SWITCHES OFF. Ipso facto. We know the F/O was PF from the report. If the F/O stopped flying the aircraft and reached down to move the FCS from cutoff to run the captain would've plainly seen the whole thing. I can't imagine "why did you cutoff?" would be his words of choice! More like "WTF ARE YOU DOING?!?" More to the point, if the PF (F/O) did stop flying and reach down to cut one engine off, the captain would have had time to either stop him flicking the second FCS off or at least quickly flick them both back to run and potentially save the day. This plainly did not happen. So it was almost certainly the PM (Capt) that moved the fuel control switches.

So what would make the PF ask the PM "why did you cut off?" if he couldn't see it happen? You would never assume with a loss of thrust that the switches had been turned off. Never. It's not a procedure. It's not a thing. Bird strike? Sure. Fuel Contam? Maybe. But the point is, in the heat of battle at 150 odd feet, you'd never jump to the conclusion that the fuel control switches were off. Never. So what triggered the PF asking the PM why he cutoff? Because he HEARD the fuel control switches move from run to cutoff, that is why. He heard those distinctive *CLICK* sounds (and yes, you can easily flick them both in less than a second FWIW) followed by the engines immediately rolling back. He would then have looked down at the switches and noticed they were in cutoff. The point to be made here is that the switches were moved by the captain. They made their distinct sound. There were no phantoms. They cannot move on their own. They didn't simultaneously fail. This drew the PF's attention away from flying and triggered the question "why did you cutoff"?

Inadvertent selection of the wrong switches? No. The PM was a training captain with thousands of hours experience on the jet. I asked one of our most experienced examiners how many times he'd seen that done. The answer was "zero". Even the stab switches next to them. They're red, guarded and are of a completely different shape and operation. Gear or flap? Come on. I think we're starting to stretch things a bit now. EVEN IF it was inadvertent switching. The INSTANT you'd made that error, you'd go "oh whoops", and flick them back to run. I know startle... I teach it. This is different. You don't flick the fuel control switches off, hear the engines roll back and sit there wondering what happened for 10 seconds AFTER THE F/O JUST ASKED YOU IF YOU CUTOFF! You did something that had an instant effect on the flight. The report indicates that "why did you cutoff" was asked just after both engines rolled back. But it took another 10 seconds to flick the FCS' back to run. If it was inadvertent, the instant the other pilot called out your error you'd correct it. The report makes it clear that there was 10 seconds between that happening. 10 seconds is a LIFETIME in that situation. The training captain knew what he was doing. He only switched the FCS' back to run once he knew it was moot.

So, why did he respond that he didn't move the switches? As per other input from people on here, when people are suicidal they often want to throw authorities off their trail. Or maybe he wanted to confuse the F/O so he didn't flick them back to run himself, or to just buy himself more time while the F/O tried to wrap his head around things? Maybe he didn't want the F/O to die knowing it was a suicide mission. Maybe we'll find out more in the final report or police investigation if things proceed that way. Maybe we'll never know.

I acknowledge that this is my opinion and of course there could be things we don't yet know about, but I must say I'm surprised that some of the theories on this professional pilot forum are no more coherent or logical than those being sprouted on social media.
This is likely to be very close to the final report. The switches moved themselves and all the other nonsensical scenarios being brought up make zero sense and in most cases simply could not happen.
As to not putting out the CVR there is always tremendous outside pressure on an investigation of this scale. Air India is important to the nation. As someone else mentioned when the final report is published it will be old news. Time works for Air India in this case. They appear to finally be making solid progress on a return to financial solvency. The powers to be are not going to jeopardize that turnaround. The answers will come with the final report at a time when it will do far less damage to Air India.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): CVR  Fuel (All)  Fuel Cutoff Switches  Human Factors  Pilot "Why did you cut off"  Preliminary Report  RUN/CUTOFF  Switch Guards  TOGA

Sailvi767
July 17, 2025, 19:39:00 GMT
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Post: 11924609
Originally Posted by EDML
Totally wrong.

The TCMA shuts down one or more engines - but it doesn't move the switches to cut-off in any magical way. TCMA directly operates the fuel valves - but the switches stay on.
Of course there is no entry for the switches being operated on the EAFR when TCMA shuts down an engine!
The displayed EICAS messages are very different when an engine is shut down via the fuel cutoff switch vice other reasons. The EAFR records those messages. I am quite sure they have eliminated the TCMA as a problem in this accident.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): EAFR  EICAS  Fuel (All)  Fuel Cutoff  Fuel Cutoff Switches

Sailvi767
July 18, 2025, 01:32:00 GMT
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Post: 11924794
Originally Posted by appruser
Apologies for the delay in responding to your posts. I see that you and others have stepped in, thanks.

I think for various reasons the ADSB data's absolute values are offset by some amount, for possibly all of the parameters. But there should be consistency in the deltas for the timestamp (by receiving station), the raw baro altitude, the Flightradar24 AGL values, and the airspeed. Flightradar24 themselves note that for altitude " ... the data is not above ground level, but it is consistent to itself."

08:08:46.55 ... 575ft ... 21ft ... 184kt
08:08:48.14 ... 600ft ... 46ft ... 179kt
08:08:48.61 ... 600ft ... 46ft ... 177kt
08:08:49.01 ... 600ft ... 46ft ... 177kt
08:08:49.46 ... 625ft ... 71ft ... 177kt
08:08:49.92 ... 625ft ... 71ft ... 174kt
08:08:50.39 ... 625ft ... 71ft ... 174kt
08:08:50.87 ... 625ft ... 71ft ... 172kt

From the Preliminary Report's airport cctv picture, the RAT was seen deployed at, by my estimate here , 150ft baro altitude, between 4-7 seconds after rotation. So the ADSB readings have to be prior to that.

What's interesting is that the ADSB data covers:
- 4-5 seconds of time (let's approximate 4 seconds from 46.55 to 50.55, ignoring the 0.32s for the moment)
- 50ft of altitude gain
- Declining airspeed from the 1st reading to the last in this final segment from the runway.

Big questions in my mind:
1. If the loss of ADSB corresponds to the E1/E2Fuel Cutoff switches being moved from RUN -> CUTOFF, why is the airspeed declining for the prior 4 seconds?
2. In 4 seconds, why is there only 50ft of altitude gain? that seems odd.
3. To account for only 50ft of alt gain, if we assume the 1st reading is on the runway just before rotation, the intermediate +25ft alt gain is at rotation (Nose up but MLG still on the runway), and the last 4 readings are in the air (nose up an additional 25ft), that means that 1 second or less after lift-off, ADSB was lost - this is before E1/E2 FCO RUN-> CUTOFF.

It's just weird .
I am not sure why 50 feet in 4 seconds seems odd right after liftoff in a heavy aircraft. That corresponds to 750 FPM. Seems entirely normal to me. The rate would have been increasing as the timeline advanced. I would also point out that RAT deployment verses the rat coming online fully are two different times. When that RAT is singled to deploy it bangs out nearly instantly. It begins producing its rated electrical and hydraulic power sometime after deployment.
The widely watched video shows a very normal initial rotation and climb.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): ADSB  FlightRadar24  Fuel (All)  Fuel Cutoff Switches  Hydraulic Failure (All)  Parameters  RAT (All)  RAT (Deployment)  RUN/CUTOFF