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framer
2025-06-14T00:58:00 permalink Post: 11901048 |
I\x92ve worked many cases in which we had a very clear, comprehensive, understanding, months or at worst several years before it was shared. I do understand why SIAs take so long, I just came to realise there\x92s no reason for it, and I\x92ve seen the damage it does.
Subjects: None 2 users liked this post. |
framer
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 KansaiOn 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.Subjects: Biocide Dual Engine Failure Engine Failure (All) Fuel (All) Fuel Contamination |
framer
2025-06-14T22:34:00 permalink Post: 11901910 |
Now, if I assume the speculation that the RAT deployed is correct, I keep coming up with two potential scenarios that could explain what's known regarding this accident:
1) TCMA activation shutdown the engines or 2) The fuel cutoff switches were activated. I literally can come up with no other plausible scenarios. Am I right in saying, from a mathmatical perspective, that dual engine flame out due biocide overdose would be more likely than a TCMA activation shutting down the engines? Considering we have examples of engines reducing to idle within seconds of each other in the past, but we have no examples of airborne TCMA issues I would have thought this to be the case. Likewise, nefarious intent also appears more likely statistically than a TCMA issue. I have high-school level statistics under my belt so I pose that as a question for people much smarter than myself. Subjects: Biocide Fuel (All) Fuel Cut Off Switches Fuel Cutoff RAT (All) RAT (Deployment) TCMA (Activation) TCMA (All) |
framer
2025-06-15T05:40:00 permalink Post: 11902123 |
You chaps not actually referring to the erroneous 767 ILS approach at Faleolo?
"
The airline won numerous awards for its world wide promotion of the incident and lessons to be learnt, produced a video available on Y'tube as "NZ60 Erroneous ILS Incident, Apia"
​​​​​​​Edited to say Ollie posted at the same time. Subjects: None 3 users liked this post. |
framer
2025-06-15T11:02:00 permalink Post: 11902360 |
True, all we know from the data is that the aircraft was barely airborne (around 40 feet) with about 1650 feet to go before the runway end.
Subjects: None |
framer
2025-06-17T10:59:00 permalink Post: 11904202 |
There is a possibility that doesn\x92t get much air time on this forum that satisfies all the \x91facts\x92 ( pprune facts mind you), and requires less mental gymnastics to believe than many of the theories put forward. I\x92m not saying it\x92s what happened at all but it seems much more likely than a TCMA fault to me.
This link is to a Japanese report on a Jetstar 787-8 with GE engines that had both engines drop below idle while airborne due to magnesium salts effecting the operation of the FSV spools. The Magnesium salts came from a biocide dose by maintenance two days earlier. For some reason I can\x92t paste the link but if you google JTSB the report number is AI2020-2. I think it\x92s quite easy to imagine that a simple maintenance error ( 1000ppm instead of 100ppm) combined with extremely bad luck on timing lead to this accident. I think I\x92m favouring a theory like this for its simplicity and the fact that fuel is the elephant in the room when you are dealing with a dual engine failure. Subjects: Biocide Dual Engine Failure Engine Failure (All) Maintenance Error TCMA (All) 9 users liked this post. |
framer
2025-06-17T12:03:00 permalink Post: 11904244 |
That’s really interesting, I’d not heard of that incident. The report does say though that particular biocide had been withdrawn due to other engine thrust occurences.
From what I can gather the biocides are required to be injected into the refuelling line with a special little wheel mounted pump in order to ensure it mixes evenly. Even something as simple as a U/S piece of kit and a late night work around could be problematic. A day before the Jetstar engines rolled back we didn’t know that that particular brand was only 7% soluble in Jet A1, yet it was. Is it possible that another brand has another issue? Or that a fantastic brand of biocide is used excessively? Or that no biocide is used at all and the actual microbes clog the spool/ filter instead of other particulates? Or any other number of things. I know it’s unlikely, but something unlikely has definitely happened, I just wanted to point out that it may surprise us all as to how simple it is in retrospect. As a side note, according to a quick internet search the biocide in question was rebranded with a slightly different name and is still available for purchase. ( not saying that it’s being used in Airliners, just that it’s still out there waiting to clog up your D8) Subjects: Biocide |
framer
2025-06-17T12:13:00 permalink Post: 11904249 |
4. PROBABLE CAUSES
In this serious incident, it is highly probable that, when the Aircraft was descending for landing, there occurred oscillation in rpm of each engine causing both engines to temporarily fall below idle at separate times because Residue primarily composed of magnesium salts accumulated in spools impeded movement of spools that involved in fuel metering of both engines. (emphasis added) One ENG Fail alert was at 1857hrs ( local) and the other ENG Fail alert was at 1858 hrs. Subjects: None 1 user liked this post. |
framer
2025-06-18T00:19:00 permalink Post: 11904793 |
Regarding the momentum: As the first seconds of the climb were normal compared to previous T/Os of the same flight (speed & altitude, confirmed by comparison of the RAW ADS-B data) I don't believe the engine failure happened before or on lift-off.
PM: “ V1 ….Rotate” The PF then begins to rotate the aircraft up to a pre determined attitude which is normally between 13 and 15 degrees. They do this at a rate of between 2 and 3 degrees per second so about 5 or 6 seconds later the aircraft is at its climb out attitude. The PM is then looking at their instruments to confirm that the aircraft has a positive rate of climb, this takes a moment, maybe 1 to 3 seconds then; PM “ positive rate” PF: “ gear up”. So minimum 8 seconds but probably longer between the PM calling “rotate” and the gear being selected up. The relevance of all that is to say that if you suspect that the gear up cycle has been interrupted by a dual engine failure, then the engines may well have been producing thrust up to an altitude of 50-100ft or so, which ties in nicely with the max height reached, distance travelled etc. Mods this is clearly not a theory, just info for those who don’t fly airliners to aid understanding. Subjects: ADSB Dual Engine Failure Engine Failure (All) Gear Retraction V1 11 users liked this post. |
framer
2025-06-18T10:45:00 permalink Post: 11905125 |
What would they do?
Subjects: None 1 user liked this post. |
framer
2025-06-20T01:15:00 permalink Post: 11906521 |
User989 thanks for a nice summary
I am at risk of turning into one of those folks who gets their mind locked on one possibility and keeps banging on about it but here goes;
2. Fuel contamination
No other aircraft affected, no measures taken at airport. Simultaneous flameout due to contaminated fuel very unlikely. 1/ No other aircraft being affected 2/ No measures taken at the airport 3/ No AD’s from the regulators 4/ No grounding of 787’s 5/ Flight profile 6/ Rat deployment etc etc I agree with your statement that dual flameout due fuel contamination is very unlikely, but we ARE dealing with something that is very unlikely. I favour the theory because an error in treating the fuel is so predictably human and simple, and a dual engine failure being related to fuel is also a simple and obvious idea, and it satisfies all we know both about the aircraft’s behaviour, and the authorities behaviour post accident. I posted a report earlier of a 787-8 powered by the same engine type have both engines roll back sub-idle within a minute of each other while airborne due to this, so we know it can happen in theory. Now……I want to be clear that I’m not saying I think I know what happened, I’m an average Joe with my hands full just flying the line, but I am a bit surprised that the idea of ‘fuel contamination specific to that airframe’ doesn’t get discussed more on this thread. Thanks again for the clear summary of discussion thus far. Subjects: Dual Engine Failure Engine Failure (All) Fuel (All) Fuel Contamination 6 users liked this post. |
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