Posts by user "Mr Optimistic" [Posts: 10 Total up-votes: 0 Pages: 1]

Mr Optimistic
June 12, 2025, 12:18:00 GMT
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Post: 11899152
Originally Posted by Del Prado
650 feet was mentioned. Can anyone confirm if that was height or altitude? (And what airfield elevation is)
BBC reckons
The last signal was received seconds after take-off, according to Flightradar24, when the plane was at 625 feet (airport altitude is about 200 feet).

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): BBC  FlightRadar24

Mr Optimistic
June 12, 2025, 16:44:00 GMT
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Post: 11899453
Can anyone comment on the adsb ground speed data on the take off roll compared to typical v1 speed ?

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Mr Optimistic
June 14, 2025, 21:39:00 GMT
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Post: 11901865
Originally Posted by BugBear
TCMA

Which side of V1 does TCMA lurk? If a pilot closes the throttles to abort, does the system allow it? After all, "too low thrust" is outside the contour....

Ya know, when every conceivable possibility (or close) has been de wormed, it"s usually something impossible, or too fearful...(Or dishonest, fraudulent, criminal ....etc ,?
From tdracer
However, TCMA is only active on the ground (unfamiliar with the 787/GEnx TCMA air/ground logic - on the 747-8 we used 5 sources of air/ground - three Radio Altimeters and two Weight on Wheels - at least one of each had to indicate ground to enable TCMA). TCMA will shutdown the engine via the N2 overspeed protection - nearly instantaneous. For this to be TCMA, it would require at least two major failures - improper air ground indication or logic, and improper TCMA activation logic (completely separate software paths in the FADEC). Like I said, very, very unlikely.

Subjects (links are to this post in the relevant subject page so that this post can be seen in context): FADEC  V1  Weight on Wheels

Mr Optimistic
June 15, 2025, 00:11:00 GMT
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Post: 11901982
SLF here. Nothing to add but I am impressed by whoever made the mayday call in those extenuating circumstances. Aviate and navigate are no longer an option but it takes calm presence of mind, fortitude and professionalism to do that.

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

Mr Optimistic
June 18, 2025, 01:27:00 GMT
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Post: 11904825
Slf
I have read that below 400 ft the crew sit on their hands.
I have read that if there is a loss of thrust the crew will firewall the thrust levers.
Everything, the rat,the flightpath,grandma hearing no sound, points to almost simultaneous loss of thrust shortly after rotation.
So,if the recorded data shows the crew firewall the t/l but the engines didn't respond, and the recorded data didn't give any causality,wouldn't you have to ground the fleet ?



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Mr Optimistic
July 13, 2025, 05:35:00 GMT
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Post: 11921034
I suppose this event will be a setback for any ambition for single pilot operation.

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Mr Optimistic
July 14, 2025, 07:59:00 GMT
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Post: 11921929
As reported yesterday by the FT

The US Federal Aviation Administration has issued a notice to its international counterparts that fuel control switches in Boeing aeroplanes like the Dreamliner involved in last month\x92s fatal Air India crash do not pose a safety issue.

The FAA\x92s notice to foreign civil aviation authorities followed a preliminary report by India\x92s Aircraft Accident Investigation Bureau that the engines on Air India Flight 171 briefly cut off shortly after take-off on June 12.


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  Preliminary Report

Mr Optimistic
July 15, 2025, 07:07:00 GMT
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Post: 11922701
Years ago I worked on safety cases for nuclear plant. I recall that the target accident probability was typically 10^-9 per year or whatever with a common mode override of 10^-6, the latter a sort of unknown unknown limit.
However this related to inanimate stuff and assumed you had trained operatives.
If you had to factor in a bad actor feature into the probability chain what probability would you assign to that little component, surely not 10^-6, could you assign a universal factor anyway and is that scenario compatible with the traditional way of designing to limit accidents ?

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Mr Optimistic
July 15, 2025, 18:49:00 GMT
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Post: 11923176
Originally Posted by OldnGrounded
Absolutely. The attempted reading of tea leaves to interpret what the authors may have meant beyond what they said, or what they intended to convey by not saying something else, may be fun for some, but it really contributes nothing to understanding this crash.

We know with reasonable (although not perfect) certainty that the fuel control switches were placed in CUTOFF almost immediately after rotation and were later moved back to RUN. We do not know who did that or why it was done and we don't have nearly enough information to answer those questions with any confidence.
The authors of the report have access to the full cvr. They have chosen to only release a synopsis of one fragment. Who knows what the rest of the cvr discloses but the decision to release that one fragment must be to convey an understanding...they want it known.

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  RUN/CUTOFF

Mr Optimistic
July 15, 2025, 19:26:00 GMT
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Post: 11923197
Originally Posted by OldnGrounded
You're making things up, attributing motive where you cannot possibly know motive. You're just guessing, and conveniently making your guesses match your preferred scenario. It is entirely possible, indeed it is the way it is supposed to be done, that the investigators have included what is known with reasonable certainty, and known to be relevant, at this point and not included other things about which they are uncertain.

It's certainly possible that we will someday learn that the Indian investigators have been conducting a manipulative campaign and using the preliminary report as an instrument of that campaign, but there is absolutely no evidence of that currently available to us now.

I think you misunderstand me. I agree with your first paragraph. The point I thought I was making is that the investigators wish to convey that the evidence points to human action. ( and not, for example, the number of poles on a switch).
Why the person in charge of the hand did that is unlikely ever to be known.

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