Bleed Air Selections
Can anyone tell me whether the starter button was pressed at all during the starter assisted relight procedure in this incident?
I seem to remember the QRH goes straight from windmill relight to APU assisted relight but doesn't highlight the subtle differences between the two procedures.
My observations in the sim were that approximately 75% of crews would need to repeat this exercise due to an inability to achieve the required N2 RPM during the starter assisted relight procedure because the QRH gave the impression that you needed at least 15% N2 prior to operating the starter button because this limit was written adjacent to the 90 degree ITT limit which you did indeed have to achieve before moving the start/thrust lever.
You would only get the 15% N2 after selecting start, a point the majority of crews failed to realise. The crucial difference being that the limits apply prior to initiating a windmill start but mainly only apply after an assisted start is initiated but before the start lever is moved.
We didn't see this as a major issue however as we considered a double engine flameout highly unlikely!!
Our management were reluctant to prescribe to captains an altitude limit and our flightplans were always giving cruise altitudes of FL360 and FL370 regardless of performance capability and the existance of an optimum FL was never discussed during briefings, the general perception being higher is better.
With this level of ignorance within the management and line pilot communities we were very fortunate not to have a similar incident.
Last edited by hec7or; 10th Jul 2005 at 15:34.