Hello TD;
Re
post #330:
My first questions would be aren't the thrust levers already in the climb detent? Does the thrust lock latch a 84% N1? if so, does this give much time to figure the right pitch and power setting before a real stall warning occurs?
Yes, you're correct - the TLs would be in the CLB detent already. The drill merely ensures that this is so, just in case they have been moved out of the detent for any reason.
Yes, again correct - the Thrust Lock would synchronize with the aircraft parameter at the time of disconnect. Eighty-four percent is sufficient to maintain stable flight for the time needed to bring out the QRH, (which should always be right at hand). The page hasn't changed in quite some time, (2.21 in Nav Abnormals). In fact a five-degree pitch attitude results in a gentle climb of around 800 to 1200fpm, (again, I was wrong on the original statements) - for an experienced crew, this would not present a problem as "close to nothing" has changed and one can return to level stable flight with tiny movements on the stick and observing the altitude and altitude trend, (rate of change). Digital vice analogue adds a cognitive step because the notion of "amount-to or -away from" is missing - no big deal.
But when I see the tables, the reset for pitch is 3.5º and 90% N1 for a M of .82 based on altitude and weight. This seems a little low on N1% with a 3.5º pitch setting based on what is referenced in the BEA report for level flight at the altitude being experienced. I recognize at the upper end of the power settings at 350 there isn't much power left to be had, but the differences seem confusing to me more than anything, perhaps I am missing some finer points. Any thoughts? Is my logic off?
No, your logic is sound - it takes a significant change in pitch or power to place the aircraft at risk of overspeed or stall during this drill. The settings given are very close to what the aircraft would require but they're not exact. Going from recollection of the FCTM here...I think an answer lies in the 10T weight category intervals. The FCTM does state that the settings are approximate and that fine-tuning involves monitoring altitude using either indicated or GPS altitude:
LEVEL OFF AND STABILIZATION (IF REQUIRED)
The table gives the proper pitch and thrust values to stabilize level flight according to weight and altitude.
If the altitude information is unreliable, the FPV and V/S are also affected. In this case, the GPS altitude, if available, is the only means to confirm whether the aircraft is maintaining level flight.
When the altitude information is reliable, use the FPV.
If the FPV is reliable, or if the GPS altitude is available:
‐ Maintain level flight (FPV on the horizon or constant GPS altitude)
‐ Adjust thrust according to the table
‐ Observe the resulting pitch attitude, and compare it with the recommended pitch target in the table:
• If the pitch necessary to maintain level flight is above the table's pitch target, the aircraft is slow, then increase thrust,
• If the pitch necessary to maintain level flight is below the table's pitch target, the aircraft is fast, then decrease thrust.
When the pitch required to maintain level flight gets close to the table's pitch target, re-adjust thrust according to table's thrust target.
This technique permits to stabilize the speed quickly while maintaining level flight.
If the FPV is not reliable and the GPS altitude is not available (no means to ensure level flight):
Adjust pitch and thrust according to table values, and wait for speed stabilization. Expect a significant time to stabilize and important altitude variations during the stabilization.
Hope this helps.