Posts by user "Gupeg" [Posts: 5 Total up-votes: 8 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?