Posts by user "OPENDOOR" [Posts: 14 Total up-votes: 26 Pages: 1]

OPENDOOR
2025-06-14T12:43:00
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Post: 11901451
Originally Posted by MR8
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.
Is it possible to operate the fuel cut-off switches accidently?




Last edited by Senior Pilot; 14th Jun 2025 at 19:08 . Reason: Double posting of image

Subjects: APU  Bird Strike  Flap Retraction  Flaps (All)  Fuel (All)  Fuel Cut Off Switches  Fuel Cutoff  Gear Retraction  RAT (All)  RAT (Deployment)

OPENDOOR
2025-06-14T16:08:00
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Post: 11901612
Originally Posted by Pip_Pip
Indeed. All theories remain on the table until falsified - including the unpalatable ones. However, you may be overlooking Murphy's Law which tells us to expect this.

To me, it makes sense to focus on testing out theories that fit within the ambit of Murphy's Law. There is no way of knowing which of us will turn out to be right. Possibly none of us...
During the nearly two years that elapsed between AF 447 disappearing and the recovery of the flight data recorders nobody suggested that the PF might have, unwittingly, flown the aircraft, stalled, into the ocean.
AI 171 may prove to also have a totally unpredicted cause.

Subjects: None

5 users liked this post.

OPENDOOR
2025-06-15T16:06:00
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Post: 11902592
Originally Posted by Pelican
Trying to keep an open mind, but\x85.

Is no one surprised the lone survivor remembers a bang just before impact, and other things like apparently emergency lights, but has not mentioned the power going from takeoff power to nothing. Even the power change at thrust reduction altitude is often very noticeable in the cabin, so it surprises me nothing about the noise (and startle/panic) of full-power to no-power has been mentioned. I think we are getting into absurd scenarios trying to make the scenario of a simultaneous double engine failure just after liftoff fit, based on perhaps not the best evidence.
If you look at the airport video of AI 171 departing and run it at high speed backwards and forwards the aircraft follows a smooth but shallow parabolic flight path. This is consistent with a total engine shut down just after departure.

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Subjects: Dual Engine Failure  Engine Failure (All)

2 users liked this post.

OPENDOOR
2025-06-18T14:50:00
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Post: 11905306
Originally Posted by PBL
The emergency power system of the 787 surely consists of a lot more than just the RAT. The Reuters article, in its body, uses the term "emergency power generator". Now that could indeed refer to the RAT.
It could equally refer to the APU which some have suggested either started or was in the process of starting.

Subjects: APU  Generators/Alternators  RAT (All)

OPENDOOR
2025-06-20T11:17:00
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Post: 11906850
Originally Posted by Fursty Ferret
If there was even the slightest suspicion that it was a TMCA issue there wouldn't be a GE engined 787 airborne until the problem was resolved.
Looking at the GE Aerospace website they appear to offer a remote monitoring service;

Remote Diagnostics

This engine health monitoring is incorporated GE Aerospace’s self-service customer web portals, where customers can find technical updates and analysis of key engine performance trends such as oil usage, gas temperatures, vibration, rotor speed, fuel flow and more. In addition, Customer Notification Reports (CNRs) issued to GE Aerospace customers identify potential engine issues with recommended maintenance actions. The comprehensive service includes dedicated consultations for analysis of key engine performance trends to optimize fleet operations as well customized insights and maintenance recommendations.
If this was on AI 171 presumably they would already know what happened.

https://www.geaerospace.com/commerci...ital-solutions

Subjects: Fuel (All)  Fuel Pumps

OPENDOOR
2025-06-20T14:59:00
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Post: 11907036
In the CCTV footage the aircraft's flight path appears to be a parabola. If there was any thrust remaining following rotation it would be very different.

Last edited by Saab Dastard; 20th Jun 2025 at 15:27 . Reason: Quote of deleted post removed

Subjects: CCTV

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OPENDOOR
2025-06-20T15:21:00
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Post: 11907053
Not very scientific I'm afraid. I made it into a loop that runs at 4x speed forwards from take-off to just before it disappears and then reverses. It looks parabolic as the height gain is the same as the descent.

Last edited by OPENDOOR; 20th Jun 2025 at 15:40 .

Subjects: None

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OPENDOOR
2025-06-20T17:21:00
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Post: 11907147
On each engine It is fail-safed to close off fuel-feed flows by a spring that is held open by a solenoid.
This statement is factually incorrect and the actual mechanism has been explained in great detail. Read the thread.

Subjects: None

11 users liked this post.

OPENDOOR
2025-06-21T15:04:00
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Post: 11907825
In the coming weeks, as black box data is analysed and preliminary findings emerge, the world will l... Read more at: https://english.mathrubhumi.com/news...fails-rkswjyay
Informative and well written article here;

​​​​​​​ https://english.mathrubhumi.com/news...fails-rkswjyay

Subjects: None

1 user liked this post.

OPENDOOR
2025-06-21T15:29:00
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Post: 11907844
787 EAFR unit

The Enhanced Airborne Flight Recorder (EAFR) fitted in the forward and aft locations are interchangeable and appear to be able to record video.

As their power requirements are 28 VDC and just 20.5 watts it seems strange that only the forward mounted unit should have a battery backup.

T he Image Recorder growth function is used to record visual images of the flight deck instruments, flight deck, the aircraft structures, and engines as required. The Image Recorder function is capable of receiving a digital 10/100 Mbit Ethernet data stream of cockpit images and stores this data in the Crash Protected Memory in a separate partition. Even though the image recording duration will be governed by regulations, the EAFR Crash Protected Memory capacity has the storage capacity for two hours of image data recording per EUROCAE ED-112 requirements. Data in the Image Recording Crash Protected Memory partition can only be downloaded when the EAFR is off the aircraft.
https://www.geaerospace.com/sites/de...rder-3254F.pdf

Subjects: DFDR  EAFR

OPENDOOR
2025-06-21T15:56:00
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Post: 11907869
The tail seemed to be intact from many post crash pictures and one would assume the boxes are there?
I don't understand why we are told they were badly damaged.
​​​​​​​The aft mounted unit may have lost electrical power at the critical moment so they might be relying on the forward unit which may have sustained damage.

Subjects: None

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OPENDOOR
2025-06-21T18:11:00
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Post: 11907957
Originally Posted by ignorantAndroid
When it stops receiving power from the aircraft. The RIPS sits between aircraft power and the CVR. It pretty much works just like an uninterruptible power supply that you'd use with your PC.
And the $64k question will be why wasn't the identical unit in the tail section given the same UPS?

It consumes 20.5 watts so a ten minute power supply should not only be easy to integrate but also already exists and is certificated for the forward mounted unit.

Subjects: CVR  RIPS

OPENDOOR
2025-06-22T14:57:00
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Post: 11908601
Enhanced Airborne Flight Recorders (EAFR)

Whilst we wait for any announcements from the crash investigators can anybody suggest the logic behind providing the front mounted Enhanced Airborne Flight Recorders (EAFR) with a Recorder Independent Power Supply (RIPS) but not giving the identical aft mounted EAFR unit the same protection where it is less likely to suffer damage?

The RIPS unit is a certificated device that just has to supply 20.5 watts for ten minutes so cost cannot be a consideration.

Another debate that should now be had is real time telemetry. Given the number of airlines contracting with Starlink for internet services onboard their fleets uploading the data stream fed to FDR's wouldn't put a dent on the available bandwidth and the search and recovery process for FDR's would be a thing of the past.

Subjects: DFDR  EAFR  RIPS

1 user liked this post.

OPENDOOR
2025-06-22T15:40:00
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Post: 11908632
Originally Posted by quentinc
The RIPS provides power to both the recorder and to the microphones in the cockpit.... If there's no power to the microphones, there is nothing to hear. If there's no power for systems in the aircraft.... then there's not going to be much for any recorder to record.
If it has no power it won't record anything at all, like the fact that multiple electrical systems are U/S but as a limited power supply from the RAT or APU comes on-line it would have something to record. It seems to me absurd that it is not powered at all times.

Subjects: APU  RAT (All)  RIPS

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