Climb Phase Flashcards
How can the takeoff climb flight path be divided? What are the minimum climb gradients for each phase in a twin (N-1)?
Can be divided into 4 segments
1: from 35ft until gear retracted - 0.0% climb
2: until acceleration altitude - 2.4%
3: until green dot (best climb) - N/A
4: until 1500ft AGL - 1.2%
What is the gear, flap/slat and engine configuration for each of the phases of the takeoff flight path?
Gear / Flap & Slat / Engine
1: retracting / Takeoff / TOGA or FLEX
2: retracted / Takeoff / TOGA or FLEX
3: retracted / Retracting / TOGA or FLEX
4: retracted / clean / MCT
What speed should an aircraft be doing during each segment of the takeoff climb?
1: V2
2: V2
3: Accelerating to green dot (best climb)
4: Green dot
When is gross/ net flight path used? What is the difference? What is the correction that is applied for a twin? Quad?
Gross: Actual path flown by aircraft
Net: gross flight path minus a mandatory reduction - 0.8% for a twin, 1.0% for a Quad
Gross: for climb gradients
Net: for obstacle clearance
What restrictions are applied to takeoff turn procedures?
- Not turning until at least 50ft and half the wingspan above the runway
- Up to 400ft may bank up to 15˚
- Above 400ft up to 25˚ or if in USA not more than 15˚
Note: specific approval can increase to 20˚ or 30˚ depending on segment
How much must the net flight path clear all obstacles by on a straight takeoff? What about in a turn?
AoB < 15˚ = 35ft
AoB > 15˚ = 50ft
What does the takeoff funnel of a JAR-OPS straight out funnel look like?
- 90m either side of centreline at the start of takeoff flight path until end of clearway
- Expands outwards at 12.5% (7.1˚) until 300m either side of track
- Follows 300m either side of track
What does the takeoff funnel of a JAR-OPS turning departure funnel look like?
- 90m wide to start
- Expands outwards
- During turn expands outwards at 12.5% (7.1˚) until 600m either side of track
- Follows 600m either side of track
What does the takeoff funnel of a FAR straight out funnel look like?
- 200ft either side of centreline until airport boundary
- 300ft either side beyond airport boundary
What allowances must be made for wind on T/O?
- not less than 150% of REPORTED TWC
- not more than 50% of REPORTED HWC
What is the effect of increase pressure altitude on thrust, TOD and climb gradients?
- Decrease thrust
- Longer TOD
- Shallowed climb gradients
What is the effect of increase temperature on TOD, thrust, and climb gradients?
- When temp is below T(ref) no effect ton thrust
- Increase TOD
- Shallower climb gradients
Between what runway slope values can a runway be considered flat for an Airbus?
From -2% to +2%
What effect on TOD and ASD will an upward or downward slope have?
Upward: Increase TOD, Decrease ASD
Downward: decrease TOD, increase ASD
What is the definition of a dry runway?
One that is not wet or contaminated
It includes paved runways that are specially prepared with groves or porous pavement to maintain effectively dry braking action even when moisture is present
What is the definition of a damp runway?
when it is not considered dry by the moisture does not give it a shiny appearance
What is the definition of a wet runway?
- RWY surface is covered with water with a depth less than or equal to 3mm, or
- Sufficient moisture for reflective appearance but without significant areas of standing water
What is the definition of a contaminated runway?
When more than 25% of runway surface area within required length is covered by the following:
- Standing water (greater than 3mm)
- Slush
- Wet snow
- Dry snow
- Compacted snow
- Ice
What will a hard runway contaminant (Snow/Ice) compared to a fluid contaminant (water/slush/wet snow) do to an aircraft?
Hard: Reduce friction forces
Fluid:Reduce friction forces, cause precipitation drag, aquaplaning
How does wet vs contaminated runway affect ASD? What may be taken into account?
- Has no effect on ASD
- Reversers are allowed to be accounted for as soon as the runway is not dry
Where does the net take off flight path begin?
35 ft above the take-off surface at the end of the take-off distance
Why may it be possible to achieve greater takeoff payloads on a wet/contaminated runway than on a dry runway? Is this allowed?
Reverse thrust is allowed when determining ASD on a wet runway but not dry, so when ASD is the limiting factor it will be shorter.
-JAR-OPS: “On a wet or contaminated RWY the take-off mass must not exceed than on a dry runway in the same conditions
How can RTOW be determined on an Airbus? What does RTOW stand for?
Regulatory Take-off weight
-Can be done using onboard computer systems or paper RTOW chart
What things will a RTOW chart tall you for a given Airport, runway and conditions?
- MTOW
- V1, Vr, V2
- What is limiting the MTOW
What is the purpose of performing a Flexible or derated takeoff? Why is it possible to perform a flex/derated take-off?
- Increases engine life and reliability, reduces maintenance costs and operating costs
- Possible due to actual take-off weight often lower than the maximum RTOW
What is a Flexible take-off?
-Take-off at a REDUCED take-off thrust. This thrust is called flexible thrust
How is a Flex t/o done? What is the limit to the thrust reduction?
- If actual TOW is less than max TOW in the conditions from RTOW chart, the flex temp for when the max TOW is the actual TOW can be found and inputted into the FMC.
- Limited to a max thrust reduction of 25% of max take-off thrust in the conditions
On what condition runways (wet/dry/contaminated) may a flex t/o or derated t/o be performed?
- Only on dry and damp unless extra stopping distance on wet surface is taken into account
- Airbus allows for a flex takeoff on wet runways as FCOM and RTOW chart provide performance info for wet runways
- Derated t/o may be performed on all runway conditions
What is a derated take-off? How is done?
- Where take-off thrust is less than the maximum t/o thrust
- Engines are ‘derated’ into different levels, and the takeoff thrust desired can be considered the maximum for the ‘new’ derated engine
How does derated t/o differ from flexible t/o?
- the takeoff thrust is considered as a normal take-off operating limit
- a separate set of t/o limitations and performance data is available for each different derate level
How does a derated t/o affect V(MCG) and V(MCA)? Describe how will it affect MTOW?
- Reduces both, and yawing moment will be less in critical engine fails
- Can increase MTOW on short runways as V1 must be above M(MCG). where ASD is the limiting factor a lower V(MCA) will reduce V1 and therefore lower ASD
When may TOGA thrust be applied during a flex or derated takeoff?
Flex: whenever required
Derate: only once airborne, due to different min control speeds
Can a flex take-off be combined with a derated take-off?
No
What aerodynamic conditions will achieve the the max climb gradient for a given weight and engine rating?
When thrust - drag is minimum
AKA: when L/D ratio is max
What speed achieves the best L/D ratio?
Green Dot
What aerodynamic conditions will achieve the the max rate of climb for a given weight?
When TAS*(thrust-drag) is max
AKA: the there is the greatest excess thrust
What is the relationship between best rate speed and best gradient speed?
best rate of climb speed is greater than best gradient
Vy > Vx
What is the effect of pressure altitude and temperature on climb gradient and rate of climb?
Increase temp: decrease RoC and gradient
Increase PA: Decrease RoC and gradient
What is the effect of Weight and wind on climb gradient and rate of climb?
Increase weight: Decrease RoC and gradient
Headwind: N/C to RoC, Increase ground gradient (no change to air gradient)
Tailwind: N/C to RoC, decreased ground gradient (no change to air gradient)
When is the climb ceiling reached?
when rate of climb is 300ft/min
What happens to mach when climbing at constant TAS
Mach increases
What happens to TAS in a climb at constant Mach?
Decreases
What speeds should an aircraft climb at for a high or low cost index? TIME/FUEL?
Low CI (fuel expensive): IAS(econ) = Vy
High CI (time expensive): IAS(econ) = V(mo)/M(mo) minus buffer (normally -10kts)
How is the cabin climb managed? What is the max rate of cabin climb?
Manages by FMGS
Limited to maximum of 1000ft/min
What re the climb gradients in a Quad engine aircraft for the 4 segments of the takeoff?
1: 0.5%
2: 3.0%
3: 0.0%
4: 1.7%
In the case of a drift-down procedure in a Quad, what is the gradient penalty applied to the net flight path for N-1 and N-2?
N-1: 1.6%
N-2: 0.5%
