En-Route Phase

Question 1

What is a drift down ceiling?

Answer 1

• 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

Question 2

What is gross drift down flight path vs net drift down flight path? What is the reduction/buffer for a twin?

Answer 2

Gross: Actual path followed by a/c after engine failure
Net: Gross flight path minus a mandatory reduction

1.1% reduction

Question 3

What is the time limitation for a twin aircraft for a departure alternate? What conditions?

Answer 3

1 hour at 1 engine INOP cruise speed

Still air

Question 4

What lateral deviation must be accounted for when conducting obstacle surveys? FAA vs JAR?

Answer 4

FAA: 5 STATUTE miles always

JAR: 10nm unless a/c can meet RNAV 95% requirement then it becomes 5nm

Question 5

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?

Answer 5

-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

Question 6

Describe each fo the two conditions for obstacle clearance margins in the en route phase after an engine failure?

Answer 6

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

Question 7

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?

Answer 7

Net flight path must have a positive gradient at 1500ft AGL at AD of intending landing
Dumping fuel may be considered if available

Question 8

Why does an aircraft have to descend to different levels after a depressurisation?

Answer 8

• Due to the oxygen profile of the system

- Oxygen is limited and will flow at different rates depending on altitude

Question 9

What must the relationship between the oxygen profile (altitude/time or distance) relate to the aircraft performance profile?

Answer 9

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.

Question 10

What sort of descent should be carried out for an emergency descent on oxygen?

Answer 10

• Speed is V(mo) or M(mo)

- Speed brakes can be used

Question 11

What is the min flight altitude above mountainous terrain?

Answer 11

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

Question 12

Is a net flight path required for a cabin depressurisation?

Answer 12

No - only required when when there is a risk aircraft cannot maintain expected descent performance (engine failure)

Question 13

In a depressurisation with all engines what is the standard descent path obstacle clearance buffer?

Answer 13

Descent profile must clear all obstacles by 2000ft

Question 14

During route studies simultaneous engine and pressurisation failures are not considered. What must limiting profile be based on?

Answer 14

• The most penalising descent profile

- If possible the same critical points and escape route should be defines for both (to reduce error and complexity)

Question 15

What costs does direct operating costs include?

Answer 15

• Fixed costs
• Flight time related costs
• Fuel consumption related costs

Question 16

What is specific range? definition and equation?

Answer 16

-Distance covered per unit of fuel

Specific ground range = groundspeed ÷ fuel cons per hr
SGR=Gs/ff

Question 17

What things will increase the specific ground range?

Answer 17

• Flying at a higher mach number/TAS

- Flying at a better Lift/Drag ratio

Question 18

What is M(mr)? Definition?

Answer 18

Maximum range mach number

• min fuel cons for given distance
• max range for a given fuel quantity

Question 19

What is the relationship between mach number and specific range?

Answer 19

-SR increases as M increase to max at M(mr) and then decreases as M increase

Question 20

How does M(mr) change as weight decreases (fuel is burnt) for a given altitude? How does SR change with weight at a given altitude?

Answer 20

M(mr) will decrease linearly

SR will increase

Question 21

How does M(mr) and SR change with increasing altitude at a given weight?

Answer 21

M(mr) will increase

SR will increase

Question 22

What is M(LRC)? Definition?

Answer 22

Long-Range cruise mach number

• SR corresponds to 99% of max specific range, but offers a significantly higher cruise mach number
• By decreasing SR by 1% gives large increase in cruise mach number

Question 23

How does M(LRC) change a weight decreases at a given altitude?

Answer 23

Decreases non linearly

Question 24

What is M(Econ)? Definition?

Answer 24

Economic mach number

-best cruise mach number considering all direct operating costs

Question 25

What is cost index? Equation?

Answer 25

-time and fuel cost ratio CI = Cost of time ÷ Cost of fuel

Question 26

What happens to M(Econ) if CI increases or decreases? Think about the equation

Answer 26

Increase CI: M(Econ) increases | Decrease CI: M(Econ) decreases

Question 27

What does it mean if CI is at it maximum or minimum values? What speeds are best?

Answer 27

Ci Max: flight time costs are higher and fuel costs low - fly at M(mo)-0.02 or V(mo)-10kts Ci min: flight time cost are null and/or fuel costs are high - fly at M(mr)

Question 28

When flying at a fixed mach number how will fuel consumption change as weight decreases for a given altitude?

Answer 28

It will increase away from the optimum

Question 29

When flying at constant mach, how is the aircraft operating at the optimum altitude? What is the L/D ratio

Answer 29

At the max lift to drag ratio for than mach number

Question 30

What are the variables when an aircraft is cruising at the optimum altitude for a given mach number? remember CL is fixed and corrosponds to (CL/Cd)max What is the equation to represent it?

Answer 30

Weight Outside static pressure Weight ÷ Static pressure = Constant

Question 31

What is the relationship between weight and optimum altitude for a given mach number?

Answer 31

-As weight decreases optimum altitude increases

Question 32

How does M(mr) and SR change with a headwind vs tailwind?

Answer 32

Tailwind: SR increases, M(mr) decreases Headwind: SR decreases, M(mr) increases *Speed changes because you want to fly in tailwind for longer and headwind for shorter time

Question 33

What is the max engine limited mach number for a constant altitude and weight determined by?

Answer 33

The EGT The engines have limited max cruise rating, depending on OAT.

Question 34

What is the max CRUISE altitude for a given weight determined by?

Answer 34

The max altitude an aircraft can maintain, at max cruise thrust, when the pilot maintains a constant mach number

Question 35

How does increased mach, weight and temperature affect max cruise altitude?

Answer 35

Increasing all will decrease max cruise altitude

Question 36

What will happen to the range of available speeds at the lift ceiling? What is this sometimes called?

Answer 36

There is only one speed that won't cause a mach stall or low speed stall Also called coffin corned

Question 37

How does increasing pressure altitude affect max load factor (n(max)) and lift range?

Answer 37

``` Decreases n(max) Decreases lift range ```

Question 38

What value is the load factor buffet limit?

Answer 38

1.3, below load factors of 1.3 buffet should never occur

Question 39

How does the buffet ceiling change as weight decreases?

Answer 39

1.3g buffet ceiling increases as weight decreases

Question 40

Overall what is the max recommended altitude based on?

Answer 40

The lowest of: - Max certified altitude - Max cruise altitude - 1.3g buffet limited altitude - Climb ceiling

Question 41

What percentage does the actual specific range of an aircraft vary in a stepped climb compared to one doing a cruise climb?

Answer 41

varies by about 1%

Question 42

What are the general characteristics of an engine failure drift down procedure?

Answer 42

- Decelerate to green dot (an remain at green dot) - Thrust is MCT on live engine - Clean configuration - Obstacle clearance is from net flight path (1000/2000ft) - No time limit to get down - Max altitudes single engine ceiling

Question 43

What are the general characteristics of a depressurisation procedure?

Answer 43

- Immediate descent - Flight idle thrust - Fly at Vmo/Mmo - Speed brakes deployed - Obstacle clearance is from gross flight path - Time limited by crew Oxygen availability - 10,000ft/14,000ft ceiling limited by pax/crew O2