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Old 23rd Mar 2009, 14:04
  #114 (permalink)  
Join Date: Dec 2002
Location: Wood's Hole (N4131.0 W07041.5)
Posts: 92
From the MD11 FCOM (Systems):
Pitch Attitude Protection (PAP) reduces the chance of a tail strike during take-off and landing by adding nose down elevator if the aircraft is at serious risk of tail contact with the ground. PAP is a direct function of pitch attitude, radio altitude and pitch rate and is enabled below 100 feet RA. The pitch attitude limit will vary linearly from 30 deg at 40 feet RA to 9.5 deg at 0 feet RA.

Positive Nose Lowering (PNL) will apply 3 deg of nose-down elevator command when the FCC commands the Auto Ground Spoilers to extend at main wheel spinup. As the spoilers extend beyond 10 deg, PNL will increase the nose-down elevator command to 4 deg. The command fades out when FD mode cycles back to T/O, or if throttles are advanced for G/A.
During take-off and landing flight phases, when PAP or PNL is active, approximately 10-15 pounds of force on the control column is required to override LSAS.

Xeque: The ground spoilers are automatically retracted when #2 throttle is advanced, or they can be manually retracted if already extended. Also, with MLG spin-up, the ground spoilers will only deploy approximately 60% until NLG wheel spinup, when the ground spoilers will deploy to 100%.

LSAS stall protection: I cannot find a reference, either in the FCOM or AMM to a RA input/flight condition where LSAS stall protection is not available.

However, again from the MD11 FCOM:
...the pilot may counteract the LSAS overspeed or stall protection by pushing on the control column with enough force to defeat the LSAS elevator inputs. This force is approximately 50 pounds. If the pilot releases the control column force rapidly, LSAS will dampen the resulting elevator instability.
(my highlighting)
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