ciclo
June 15, 2025, 17:34:00 GMT
permalink Post: 11902656

water leak in the electronics bay

Would anyone know whether this AD is relevant?

FAA Orders Boeing 787 Inspections to Fix Water Leak Issues

Quote:

‍DALLAS — The Federal Aviation Administration (FAA) has adopted AD 2025‑09‑12, effective June 18, 2025, mandating inspections and on‑condition sealant repairs on select Boeing 787‑8, ‑9, and ‑10 series airplanes.

This action was prompted by reports of potable‑water‑system leaks—stemming from improperly installed waterline couplings—that allowed water to seep into electronics equipment (EE) bays, risking electrical shorts and potential loss of critical flight systems.

I add this note: the background on this AD is here:
https://www.federalregister.gov/docu...pany-airplanes
T28B

Last edited by T28B; 15th June 2025 at 17:49 . Reason: AD details

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Air Worthiness Directives FAA

ciclo
June 15, 2025, 18:52:00 GMT
permalink Post: 11902715

The report of a seat back collapsing on rotation is a poorly rehashed version of the completely unrelated Air India Express flight 611 in October 2018. That flight did have a captain seat collapse on takeoff causing it to take off with reduced thrust, flying its landing gear through the localizer array and airport perimeter wall. But it eventually diverted and landed safely with no injuries. There are even YouTube videos about it, e.g. search YouTube for "Boeing 737 flies through brick wall".

Subjects: None

ciclo
June 16, 2025, 00:58:00 GMT
permalink Post: 11903019

Quote:

Originally Posted by grumpyoldgeek

Not trying to be a smart ass, but how do you "ground test" a RAT?

Typically, one spins up the RAT using an external power source like a hydraulic motor, and checks whether the generator end of the RAT is making adequate voltage.

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

ciclo
June 16, 2025, 01:07:00 GMT
permalink Post: 11903022

Quote:

Originally Posted by fdr

Adding to your response TD, there is no time in this event where a high AOA arose prior to the final moments, around 13 seconds after the problem has occurred. AOA, intake separation is not a factor.

Going back to your prior comments on FADEC and TCMA; these are independent systems to each engine, however the event indicates a symmetric loss, and the potential of water ingress from a failed E/E sealing from the main cabin services remains a single causation that could result in multiple failures at the same moment. The last time I assessed issues in the E/E bay related to unauthorised inflight access to the fwd E/E of a B777 it was sobering how many irreversible conditions could arise. The B744 water inundation cases I was involved in were both on TO, the QF event was during deceleration. We are looking at vectors that come from outside of the normal assumptions in the SSA's, water fits that bill.

One related question: since it was reported that the packs were not functional on the previous flight and were (presumably?) fixed before the accident flight, could condensation of excess humidity in the E/E bay be a relevant mechanism?

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

ciclo
June 19, 2025, 03:05:00 GMT
permalink Post: 11905688

The seat back story

@ferry pilot and others who mentioned the seat back collapsing: That was from an entirely unrelated incident on Air India Express flight 611 in 2018 which got poorly rehashed / fakenewsed into a bogus theory over the last week. It was a 737. It did *not* happen on AI171.

For what it's worth, the AIX 611 story in 2018 involved a 737 captain's seat back being overtightened and suddenly collapsing backwards during the takeoff roll. He had been guarding the thrust levers and reflexively grabbed them when falling back, causing a thrust reduction from 98% N1 to 75% N1 or thereabouts. Control was immediately transferred to the other pilot but the inadvertent thrust change was not corrected immediately, and the plane took off a few seconds later with a tail strike, scraping the runway, flying through the localizer and demolishing part of the airport perimeter wall with its landing gear. During the climb, the flight crew ran several system checks and landing gear tests to reassure themselves the plane was fine, then proceeded with the flight, pressurizing the aircraft and whatnot. They evidently did not consult the tail strike procedure. Many hours later they were ordered by company to divert and land quickly after the damage was seen at the airport. After landing, the plane was found to have a fair bit of damage, including part of the perimeter wall's barbed wire fencing material wrapped around the landing gear. But zero injuries, and the plane was fixed and flew again.

It's an entertaining story because of the cause and the happy ending, but had nothing to do with AI171, for which we all await the preliminary report.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AI171 Preliminary Report Takeoff Roll

ciclo
June 20, 2025, 13:34:00 GMT
permalink Post: 11906977

procedural question about investigations

Quoting a media report:

Quote:

"There are nearly 1,150 Boeing 787 variants currently in service across the world, taking a snap decision on the airworthiness of the worldwide Boeing 787 aircraft would be highly irresponsible, which is why international agencies are conducting independent investigations into the June 12 crash, and if sufficient evidence is found a decision will be taken," a senior government official working alongside the international agencies told Moneycontrol.

Is it common to have multiple independent parallel investigations into an air accident? Other places have reported that the Indian AAIB has sole authority and everyone else is only a technical functionary in the investigation. Which is it?

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

ciclo June 15, 2025, 17:34:00 GMT permalink Post: 11902656	water leak in the electronics bay Would anyone know whether this AD is relevant? FAA Orders Boeing 787 Inspections to Fix Water Leak Issues Quote: ‍DALLAS — The Federal Aviation Administration (FAA) has adopted AD 2025‑09‑12, effective June 18, 2025, mandating inspections and on‑condition sealant repairs on select Boeing 787‑8, ‑9, and ‑10 series airplanes. This action was prompted by reports of potable‑water‑system leaks—stemming from improperly installed waterline couplings—that allowed water to seep into electronics equipment (EE) bays, risking electrical shorts and potential loss of critical flight systems. I add this note: the background on this AD is here: https://www.federalregister.gov/docu...pany-airplanes T28B Last edited by T28B; 15th June 2025 at 17:49 . Reason: AD details Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Air Worthiness Directives FAA
ciclo June 15, 2025, 18:52:00 GMT permalink Post: 11902715	The report of a seat back collapsing on rotation is a poorly rehashed version of the completely unrelated Air India Express flight 611 in October 2018. That flight did have a captain seat collapse on takeoff causing it to take off with reduced thrust, flying its landing gear through the localizer array and airport perimeter wall. But it eventually diverted and landed safely with no injuries. There are even YouTube videos about it, e.g. search YouTube for "Boeing 737 flies through brick wall". Subjects: None
ciclo June 16, 2025, 00:58:00 GMT permalink Post: 11903019	Quote: Originally Posted by grumpyoldgeek Not trying to be a smart ass, but how do you "ground test" a RAT? Typically, one spins up the RAT using an external power source like a hydraulic motor, and checks whether the generator end of the RAT is making adequate voltage. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): Generators/Alternators RAT (All)
ciclo June 16, 2025, 01:07:00 GMT permalink Post: 11903022	Quote: Originally Posted by fdr Adding to your response TD, there is no time in this event where a high AOA arose prior to the final moments, around 13 seconds after the problem has occurred. AOA, intake separation is not a factor. Going back to your prior comments on FADEC and TCMA; these are independent systems to each engine, however the event indicates a symmetric loss, and the potential of water ingress from a failed E/E sealing from the main cabin services remains a single causation that could result in multiple failures at the same moment. The last time I assessed issues in the E/E bay related to unauthorised inflight access to the fwd E/E of a B777 it was sobering how many irreversible conditions could arise. The B744 water inundation cases I was involved in were both on TO, the QF event was during deceleration. We are looking at vectors that come from outside of the normal assumptions in the SSA's, water fits that bill. One related question: since it was reported that the packs were not functional on the previous flight and were (presumably?) fixed before the accident flight, could condensation of excess humidity in the E/E bay be a relevant mechanism? Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FADEC
ciclo June 19, 2025, 03:05:00 GMT permalink Post: 11905688	The seat back story @ferry pilot and others who mentioned the seat back collapsing: That was from an entirely unrelated incident on Air India Express flight 611 in 2018 which got poorly rehashed / fakenewsed into a bogus theory over the last week. It was a 737. It did not happen on AI171. For what it's worth, the AIX 611 story in 2018 involved a 737 captain's seat back being overtightened and suddenly collapsing backwards during the takeoff roll. He had been guarding the thrust levers and reflexively grabbed them when falling back, causing a thrust reduction from 98% N1 to 75% N1 or thereabouts. Control was immediately transferred to the other pilot but the inadvertent thrust change was not corrected immediately, and the plane took off a few seconds later with a tail strike, scraping the runway, flying through the localizer and demolishing part of the airport perimeter wall with its landing gear. During the climb, the flight crew ran several system checks and landing gear tests to reassure themselves the plane was fine, then proceeded with the flight, pressurizing the aircraft and whatnot. They evidently did not consult the tail strike procedure. Many hours later they were ordered by company to divert and land quickly after the damage was seen at the airport. After landing, the plane was found to have a fair bit of damage, including part of the perimeter wall's barbed wire fencing material wrapped around the landing gear. But zero injuries, and the plane was fixed and flew again. It's an entertaining story because of the cause and the happy ending, but had nothing to do with AI171, for which we all await the preliminary report. Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AI171 Preliminary Report Takeoff Roll
ciclo June 20, 2025, 13:34:00 GMT permalink Post: 11906977	procedural question about investigations Quoting a media report: Quote: "There are nearly 1,150 Boeing 787 variants currently in service across the world, taking a snap decision on the airworthiness of the worldwide Boeing 787 aircraft would be highly irresponsible, which is why international agencies are conducting independent investigations into the June 12 crash, and if sufficient evidence is found a decision will be taken," a senior government official working alongside the international agencies told Moneycontrol. Is it common to have multiple independent parallel investigations into an air accident? Other places have reported that the Indian AAIB has sole authority and everyone else is only a technical functionary in the investigation. Which is it? Subjects (links are to this post in the relevant subject page so that this post can be seen in context): AAIB (All) AAIB (India)

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