En-Route Phase Flashcards
What is a drift down ceiling?
- The max altitude that can be maintained with one engine INOP when other is sex at MCT and IAS is at green dot
- Does not necessarily mean the aircraft is drifting down if the engine failure occurs at a low altitude it can be a climb
What is gross drift down flight path vs net drift down flight path? What is the reduction/buffer for a twin?
Gross: Actual path followed by a/c after engine failure
Net: Gross flight path minus a mandatory reduction
1.1% reduction
What is the time limitation for a twin aircraft for a departure alternate? What conditions?
1 hour at 1 engine INOP cruise speed
Still air
What lateral deviation must be accounted for when conducting obstacle surveys? FAA vs JAR?
FAA: 5 STATUTE miles always
JAR: 10nm unless a/c can meet RNAV 95% requirement then it becomes 5nm
What vertical clearance shall be considered when determining if a route is suitable? How should en-route net flight path be determined and the effect of ice?
-margin between the net flight path and obstructions
- Net fp: from aircraft flight manual, with account for prevailing temp and winds
- Addition consideration shall be taken if anti ice systems are expected to be used
Describe each fo the two conditions for obstacle clearance margins in the en route phase after an engine failure?
Condition 1:
-Maintain positive gradient at least 1000ft above all terrain/obstacles in the corridor
Condition 2: (If condition 1 too limiting to not possible)
- Drift down procedure determined where net flight path clears all obstacles by 2000ft between from cruise to adequate landing
- Must always be possible to escape while maintaining 2000ft vertical clearance by either Turing back, diverting or continuing
Describe the gradient of the net flight path at the aerodrome where landing is assumed to occur after engine failure? If dumping fuel able to be considered?
Net flight path must have a positive gradient at 1500ft AGL at AD of intending landing
Dumping fuel may be considered if available
Why does an aircraft have to descend to different levels after a depressurisation?
- Due to the oxygen profile of the system
- Oxygen is limited and will flow at different rates depending on altitude
What must the relationship between the oxygen profile (altitude/time or distance) relate to the aircraft performance profile?
Aircraft performance profile must always be below the oxygen profile
-If O2 can reduce flow at 10,000fpm and the aircraft can only do 8,000fpm the descent to remain below must start slightly earlier.
What sort of descent should be carried out for an emergency descent on oxygen?
- Speed is V(mo) or M(mo)
- Speed brakes can be used
What is the min flight altitude above mountainous terrain?
FAA: 2000ft within 5 sm corridor
JAR: MOCA (min obstacle clearance altitude), MEA (min safe en-route altitude), MGA (min safe grid altitude), above 10,000ft min is 2000ft above obstacles
Is a net flight path required for a cabin depressurisation?
No - only required when when there is a risk aircraft cannot maintain expected descent performance (engine failure)
In a depressurisation with all engines what is the standard descent path obstacle clearance buffer?
Descent profile must clear all obstacles by 2000ft
During route studies simultaneous engine and pressurisation failures are not considered. What must limiting profile be based on?
- The most penalising descent profile
- If possible the same critical points and escape route should be defines for both (to reduce error and complexity)
What costs does direct operating costs include?
- Fixed costs
- Flight time related costs
- Fuel consumption related costs
What is specific range? definition and equation?
-Distance covered per unit of fuel
Specific ground range = groundspeed ÷ fuel cons per hr
SGR=Gs/ff
What things will increase the specific ground range?
- Flying at a higher mach number/TAS
- Flying at a better Lift/Drag ratio
