Posts by user "go-around flap 15" [Posts: 5 Total up-votes: 0 Pages: 1]

Limahotel...

Why do you expect that? Are you in posession of the takeoff performance figures for this flight and the 2nd segment climb calculations? You are attributing something to not be possible simply due to an expectation that it can not be so?

What do you expect that the clean maneuvering speed is when compared to takeoff flap in this instance?

You may be right, you may be wrong. As may I - but to dismiss a potential and possible theory because you ' expect ' that increasing thrust and AoA would be enough is quite short sighted!

Why on earth would their speed increase if they inadvertantly retracted the flaps?! If flaps are inadvertantly selected up without the required airspeed, the nose would have to be raised to compensate for the loss of lift from the flaps in order to maintain a rate of climb/avoid a sink, which would have the secondary effect of reducing airspeed... It's genuinely frightening the level of technical knowledge on this forum.

And another: https://www.gov.uk/aaib-reports/aaib...319-111-g-ezew

In an Airbus the flap lever is even further away from the gear lever than in any Boeing, yet still it happened! Action slips are just that and to blindy say that moving the flaps before gear is impossible, just because they are in a different location is incredibly naive. Next time you pour orange juice in your tea because you were thinking about something else and grabbed the wrong carton will you decry it impossible?

To be as crystal clear: I am not saying this is how it happened, but it could be. Just as other things could be.

We're all shouting each other down with two main different theories on why the aircraft lost lift so shortly after takeoff.

1) Incorrect flap retraction causing the aircraft to lose lift and unable to recover the energy in time. (Not unheard of and plenty of reports where this has happened - albeit usually not to a crash).

2) Loss of engine thrust backed up two potential pieces of evidence that back up the RAT was deployed (apparent RAT sound, potential RAT seen on low res video).

It is impossible to know which of these is the case. Considering this summary of memory items is there the potential for a combination of both theories to have taken place?

Inadvertant flap retraction by PNF leading the PF to sense a sink and loss of lift. Pushes the thrust levers forward to the firewall and still the aircraft sinks. PF looking through the HUD and so very much 'outside focused' and doesn't realise that PNF has instead moved the flaps. PF defaults to memory items for loss of thrust on both engines before PNF can realise or communicate to PF what they've done, start switches are cut off which drops the RAT and from that point they're only heading one way. This would satisfy the strongly held belief that the RAT was extended, whilst also following the more likely initial cause of an action slip by PNF starting the sequence, rather than a dual engine failure.

It's tempting to think that, however one may also have made the case 'why doesn't Boeing install a system that prevents the nose getting too high on the 737 MAX? Then they won't have to retrain crews on handling differences'. We know how that worked out.

When designing anything you need to account for unintended consequences and the possibilities for that system adversely affecting safety if it were to malfunction. If you introduced a system designed to prevent flap retraction 20 to 30s after liftoff, what if failure in a channel of that system then prevents flap retraction required to achieve a MACG with critical terrain on departure. We could 'why don't they do this / why don't they do that' until eventually we end up with not flying at all.

On your point of integrated scales, there is a far easier way to cross check actual aicraft weight with calculated weight: a computer that cross references acceleration data on the takeoff run with known values from lookup tables based on specific environmental conditions and engine thrust settings. If you're not accelerating at a normal rate expected for the calculated thrust and weight a warning can be triggered. This was a recommendation echoed by the AAIB following the incident with a Jet2 aircraft getting airborne at only 70% thrust. I believe Airbus and Boeing are looking into the potential implementation of such a safety system.