Posts by user "Gupeg" [Posts: 13 Total up-votes: 0 Pages: 1]

Re FDR and CVR, remember the 787 uses EAFR(s) instead - one in tail and one in nose.

Comments above "they will already have been read" - suggest search and read India press links, and the (new) India AAIB lab ability to read data recorders, e.g. one timed at June 15, 2025 00:08 IST. It may well be the first 'political' issue about this accident in where the recorders are sent. If India is chosen, maybe they will take their time with a new lab, and watched over by the world and other AIB representatives? I believe the investigating state 'controls the release of information' (or not). Whilst the UK AAIB are there, as their website says they have 'expert' status, which I suspect means not a lot of involvement in the politics.

If you wanted to an analyse this further:
1. You might mathematically start at TE=0 at start of takeoff-roll, and treat drag as minimal until rotation.
2. Typically rotation will be to say 15deg nose up, but flight path will be much less (5deg? for heavy hot 787). Once that rotation is complete, aircraft will stop accelerating. Therefore engine thrust (energy gain) equals gain in PE - drag x time.
3. This might give a better insight into where energy gain/loss became unusual?

Looking at the raw data in your post, and given the speeds are likely IAS based i.e. can be affected by wind, I don't see the IAS loss as equating to dual engine failure i.e. zero thrust - but could be wrong. Once a heavy airliner gets to lift off the acceleration is reduced (drag) and the decays to zero as PE gain kicks in.

Ditto a time / distance to the crash site might give some energy info? Looks like the crash site is 50' (?) below the airfield (Google Earth will give more).

I think you are doing an interesting study on the absence of other info

Thanks for that... makes the energy analysis more accurate/relevant

As per T28B but expanding:
Part 1: Fly the aircraft in Pitch such that ground impact occurred at minimum IAS compatible with minimum RoD. If 120KIAS is stall speed, roughly 130KIAS at zero RoD.
Part 2: Fly the aircraft in Roll such that the distance flown from Part 1 was the least hazardous to aircraft occupants and people on the ground. Given the starting conditions I doubt if more than 10AoB would be practical?
Part 3: Try and do whatever to restore thrust.

At a guess Part 1 was attempted, Part 2 was hardly a choice to achieve much and Part 3 needs to await the investigation, but I surmise little could or was done.

It would be good to get an FCOM reference for this, and/or definitive answer from a current 787 pilot (if they know ).

On the A320 if the centre fuel pumps are selected on pre-start, they run for 2 mins after start and then turn themselves off until Flaps selected to 0 (i.e. well after takeoff), when they turn themselves on. As far as the crew are concerned they were selected on from pre-start onwards [long retired A320 so forgive me if in error].

If certification demands this 'complexity' it would seem surprising the 787 does not have a similar system? Are we sure the 787 centre tank 'higher pressure' pumps are:

1. Actually running on takeoff?
2. If running, they are providing centre tank fuel directly to both engines, and not, say, centre tank fuel to wing tanks, and then wing tanks to engines?

The Mods have stuck to this principle, which I shall try to adhere to.
This preliminary report is just that, but maybe consider the issues the Indian AAIB have had to address in publishing it. They will have a similar concern to the pP mods, maybe more so since any apparent accusations directed at the pilots may lead to physical retribution.
I therefore conclude great care has been taken to "sanitise" what the AAIB know, or at least strongly suspect, (from EAFR) into the report. They have conspicuously failed to identify which of the pilots was each half of the conversation they have not repeated the exact words, there's a lot missing (was positive rate ever called, was rotate ever called, any discussion about putting FC back to Run, who/how flying aircraft meanwhile). As a result we, the reader, should step back and not over-interpret this sanitised report.

Secondly, given the mod statement above, if a criminal act is suspected by the AAIB, this will likely trigger all sorts of 'primacy' issues in the investigation i.e. police? AAIB? or joint? and all the history that involves (SAS Linate?) - in Europe we have 996-2010 Article 12 para 2, but India?

Summary : For good reason I believe this report has been very carefully worded, sanitised with great care, and as such easy to inappropriately speculate what went on.

With all due respect I disagree I think the prelim report was very sanitised to achieve the aim of a prelim report (are there any urgent safety actions relevant to this accident to be addressed?) whilst avoiding 1) Extreme public reaction 2) Addressing potential criminal behaviour - which the AAIBs are not experts in, nor the correct investigatory authority.
Your final sentence similarly I doubt - I suspect the CVR does reveal a lot more - certainly the timings of the reported interactions. It's just sensitive information... The report was written at 4AM ish Indian time and released shortly afterwards, and I surmise most of the delay was not "what to include" but "what NOT to include" to (only) achieve the aims of a prelim report.
I am not trying to be disrespectful, just put forward a different point of view, and you may well be right...

I'm not sure it is amazing? All I read into the report's words is that the FCSs were turned on, I assume that this will see fuel flow to the combustion chambers and ignitors within 1s, and if the fuel ignites (why not?) EGT rises and the report records this as "relit".
The low airspeed airflow through engine and HP RPM on Eng 1 were sufficient to allow HP RPM to increase. The longer delay between Eng 2 OFF then ON allowed HP RPM to decay more than #1, and although 'relit', I read a successful (unassisted) spool up was unlikely? (i.e. a detailed unassisted relight envelope including current HP RPM and IAS would have #1 in the envelope and #2 outside).

As a wild guess, if he knew it would not succeed (and it true, was correct and recovery was not even close to being possible)

To be frank, we do not know he did not. The report has been (IMHO) carefully sanitised to remove any evidence indicating it was (or not) a suicide attempt, which pilot said what, when they said it, no indication these were the exact words, and no indication that there is not plenty more conversation available.

If we want to speculate in this area, one could ask (my best guess):

1. Do the AAIB know who said "why" and who "I did not"? (Yes)
2. Are they the exact words? (No) Or a 'summary'? (Yes)
3. Were other words spoken by one of both pilots? (Yes)
4. Do the AAIB know whether there were or were not other cockpit occupants? (Yes) Were there? (No - since to fail to mention it casts assertions on just 2 named individuals)
5. Are the AAIB fairly certain of the root cause of this accident (Yes i.e. mechanical issue, unintentional HF, unlawful interference) If yes, have the AAIB deliberately sanitised this report to conceal both the root cause, and other information that would lead to uninformed speculation that does not further flight safety (Yes)

Quote: Originally Posted by Contact Approach
But there is evidence, pretty clear evidence!
The "evidence" might be available, but I disagree it is available to us. I assert the prelim report has been deliberately sanitised to prevent us (i.e. everybody outside the AAIB circle) being given enough 'evidence' to make certain conclusions.

You/others might not like it, some might say it is obvious (I say not), but I think it is carefully worded enough to imply what might have happened, but nothing is clear - intentionally.

For historical reasons, adding CVRs (Voice/Audio) to aircraft was a controversial subject. I think there was a particular accident that led to their introduction, but involved the 'buy-in' from pilot's unions, who were able to play their part in the legislation and installation. For instance, each cockpit (at least until 10 years ago) has a CVR erase button.
Recording images/videos is prevented by similar union/regulator agreements AFAIK . It might take this accident to change that, of note the GE EAFR fitted to the 787 has the capability:
i.e. the 787 EAFRs appear to have the crash protected ability to record images/video, but not (yet?) the cameras etc. to do it.

Sorry - disagree. Even with FDRs and CVRs, pilots are ultimately controlling the aircraft, including power to the CVR/FDR etc (and CVR erase).
You seem to be advocating a "pilot proof" recording and streaming system in real time? Whilst possible, it is a big step from today, and even if the regulators / airlines / unions agreed, it would be a long time before all aircraft flying were fitted.
The current systems are designed for accident investigations, not unlawful interference by pilots. The cockpit door again is designed for unlawful interference by others than the crew (including cabin crew), and despite Germanwings and maybe MH370 (where the door was used by the crew unlawfully enabling the accident), no changes have (to my knowledge) been proposed.

There is a huge difference between Starlink letting the SLF watch videos and WhatsApp their mates, and using it to stream regulated data... in the latter case, once mandated, whenever Starlink has a glitch, or cannot logon, the flight is grounded.
Of the 5 flights I have done where the carrier advertises me a sort of WiFi service, on 3 it has never worked, one I got to send a few messages then no more and on one it was sort of useful, some of the time...

If it is optional, no airline will install it. Nil advantages - they have long had QAR data to review post flight. Before you say "live data" is an advantage, no pilot went into management to monitor flights real time at night, weekends or holidays