Enroute Limitations Flashcards
What should the drift down procedure in case of an engine failure consist of?
- Control a/c
- MCT on live engine
- Decelerate to green dot speed (best L/D)
- Create minimum drag (clean)
- Level off at drift down ceiling (max altitude for level flight n-1).
Should take 40min ish
Difference between gross and net drift down path? (Enroute)
Gross is the mean/actual path flown and must be selected with the most unfavourable CoG (fore) and with CE failed.
Net is the gross minus a mandatory reduction
— Twin (n-1) 1.1%, quad (n-1) 1.6%, quad (n-2) 0.5%
What alternate AD requirements are there if engine failure occurs during T/O and WX below landing minima on departure?
If turning back is not possible, there must be a suitable AD:
- In a twin (n-1), 1hr in still air cruising speed
- In a quad (n-1), 2hr in still air cruising speed
What is the horizontal enroute obstacle/terrain clearance with an engine failure? (Twin)
The net flight path must permit a descent from cruising altitude to AD clearing all obstacles/terrain within 5Nm (10Nm if 95% nav acc unachievable) (JAR) or 5Sm (FAR)
What is the vertical enroute obstacle/terrain clearance following an engine failure? (Twin)
Along the original route, the gradient of the net flight path must be positive at at least 1000ft above all terrain/obstacles enroute. If this can’t be met (weight too great), the net flight path to an alternate must clear all obstacles/terrain by 2000ft (check pg100 for useful diagram).
What must the gradient above the diversion airfields be? (Twin)
The net flight path must have a positive gradient 1500ft ADL. This airfield must meet the performance requirements at the estimated landing weight and WX reports/forecast must indicate a safe landing at ETA
What flight path conditions exist for a quad jet assuming the failure of 2 engines?
What about at the AD it is assumed the a/c will land at?
Net flight path must permit terrain/obstacle clearance by 2000ft and 5Nm laterally (10Nm if 95% nav can’t be met) in met conditions where n-2 occurs simultaneously to a safe AD to land at.
N-2 net flight path must have a positive gradient 1500ft ADL.
What altitude must not be operated above without supplemental oxygen?
10,000ft
What is the descent profile in the event of a cabin depressurisation limited by?
What is the cabin pressure assumed to be?
Nothing to do with a/c performance, it is due to O2 system capacity.
As the O2 increases with a decrease in altitude, less PAX are required to be supplied with O2, so the system lasts longer and produces the profile seen on pg107, based off VMO (even if WX doesn’t permit).
The cabin PX is assumed to be the pressure altitude.
What is the minimum height above terrain for IFR flights?
Not less than 1000ft above highest terrain/obstacle (2000ft if mountainous terrain) within 5Nm of track.
What is the obstacle clearance in case of a cabin depressurisation?
Net flight path not required as no performance loss due to both engines running, but have to maintain 2000ft above highest drain/obstacle.
At what point of a route study is the failure assumed to be at?
Which failure is assumed at this point?
The most critical points.
The escape route from the most critical point shall be considered the most penalising of the cabin depressurisation/engine failure.
