hec7or
As a sim instructor on this aeroplane, let me say that I fully agree with your remark about the confusion induced by the relight procedure. When a crew has been insufficiently briefed before conducting this event in the FFS, it's a cluster f**k.
I always try to stress the importance of clearly understanding the QRH checklist and its' relevance to crew survival on a cold, dark and dreary night whilst running out of airspeed, altitude and ideas. Most students are quick to point out that their company does not provide individual crew members with a QRH of their own. Pity.
(Make way for the LCC.)
Therefore, they NEED to know, that the core windmilling rpm drops to approximately 3%, give or take, even with the fan turning at 20 + %!!!
The QRH also points out "WHEN ENGINE ROTATION IS ESTABLISHED". This can only be met, IF the crew drops the nose at 26,000 feet and accelerates "to 300 KIAS or greater to achieve the required N2" as informed." Which this crew did not manage to do.
Did they not realize N2 is what governs engine starts??? Were they looking at N1 perhaps and deciding well enough? I surely wouldn't know.
The ITT must be below 90 C and the core (N2) spinning at at least 12% above 15,000 and at least 9% below 15,000. ITT reduction is generally not a factor when the aircraft has already descended from 41 to 21. But, here's the rub.
The QRH Engine Failure checklist ALSO states "if neither engine is restarted: consider a forced landing or ditching." So, at what point to abandon the start attempts? I teach that following the initial attempts to look at RPMs. Core N2 zero, you've got engine damage because they should be turning. The one that IS, should be concentrated on. Were both engines on the accident aircraft turning or not turning? That is the question.
Beanbag
How right you are.
In the clear light of day, it seems your suggestion is spot on. Unfortunately, in the clouded reality of "Holy Sh*t", some of the balls get dropped. Perhaps this is part of what happened to this crew. The hearing pointed out that there were three useable airports short of Jefferson City the crew could have accepted.
What can I say? It was their call.
et al
It surprises me to watch Human Factors at work in the sim.
We hammer these crews with SOP, SOP, SOP!!! To the point where the strictest adherence to SOPs during an emergency are more of a distraction than a solution. In some cases, you have to pull out your Ace-In-the-Hole. That's the experience card.
Computers still operate on the premise "Garbage IN. Garbage OUT."
It is seriously flawed in some cases but it's what we're given to work with, isn't it? I don't advocate NOT following SOPs but I do advocate some sort of crisis intervention on the part of the experienced crewmember. Even if the action is preceeded with the phrase "non standard" for whatever action out of expedience.
B738
(good little aeroplane the NG)
You are spot on with regard to the SPS. Holding the AP/SP push button for more than 4 seconds disconnects the pusher.
So much for the deep stall theory. And, thanks for pointing it out.
