Performance Flashcards
What determines max x wind capability for take off? (A3-21 pg162)
Impact of changing:
Vrot
GW
RCR
Controllability during acceleration, rotation and lift off.
Vrot increases (eg gust): could have increase or decrease in max x wind due to RCR.
Dry, no impact.
Above 18, higher Vrot = higher x wind (more aero control at rotate?). Below 18, higher Vrot = lower max x-wind
GW increases: max x wind increases
RCR decrease 22-18: increase in x wind… counter intuitive but possibly due to at rotate, sideslip vs roll?
RCR decrease further, x wind decreases (acceleration phase limiting)
Increases Vrot due to gusts
What other considerations?
CFL will increase.
X-wind limit will change.
All climb out speeds and emergency return add same increment.
Stab trim 1 unit ND every 10kts increase.
Beware tire placard at high GW
“If Obstacle limited” CFL should be recalculated and increased to account for higher Vrot. Re Run the numbers if RA is tight.
Change in winds as you wait at the hold. What should you consider?
Headwind change: if we haven’t taken the HW benefit, no impact except the additional safety buffer changes.
During planning and APC preflight, figure out your max gust with chosen N1 setting and brief flight deck. Have the TO page up to update as you enter runway if gusty day; Update carets.
Headwind gust: Use 100% gust regardless of wind angle! change Vrot and all climb out speeds. Changes CFL of obstacle limited.
Adjust the Vrot tgt airspeed bug.
Stab trim 1 ND per 10kt increase.
Cross wind:
Still within limits including increased Vrot?
Is Vmcg close to S1? Approx 1 kt increase cross wind = 1 kt increase Vmcg. Re run data if close.
Crosswind gust: as above. Treat as steady but use the crosswind component, wind angle matters.
Slush or water puddles
Allowed depth?
Less than 1/2 inch / 1.25cm
Can increase TODR by 25%
Don’t take off above: can damage airframe
Impact on endurance:
Altitude band
Speed band
GW band
Engine anti ice
Gear door down
Minimal impact
+- 4000ft
+- 10kts
+- 40,000lbs
-1%
-34.7%
Approach speeds based of Vref allowable under what Gw?
What are the adjustments?
200,000lb
Vref +
F50 5
F40 10
F30 20
F20 30
S1 = rotate
What to be aware of on take off roll?
Greater than 10kt headwind?
Command bars will not pop until at least GS = (Vrot tgt bug - 10)
You are expecting combined S1 and rotate call but they will no longer be coïncident. Flag this up before take off.
Call S1 at S1, rotate when bars move.
CG impact on controllability
Fwd more stable, less maneuvrable
Aft less stable. More efficient as less pitch up elevator/stabiliser lift required to maintain level flight.
Climb profile
250 kts to 10,000ft
270 kts M0.74 above 31,500ft
300 kts M0.74 above 25,000ft
Better rate (and angle) at 270 vs 300
280klb FL200 1650fpm vs 1600fpm
Step climb cruise
Set N1 to achieve M0.76 at specified altitude.
Allow speed to increase as mass reduces. Check next altitude required then use excess energy to climb at regular intervals not to exceed 30 minutes.
EFAS failure impact on Vmcg
Ensure that if efas fail Vmcg does not increase above refusal. Re plan take off for lower thrust or GW if this is the case.
Advised to abort for EFAS below S1
Vmcg may increase by up to 25 kts
Vmcg could become greater than S1
Rare scenario - EFAS fail between 90-S1, then EF at/above pre-planned S1 rendering aircraft uncontrollable if we didn’t abort for EFAS…
Max range cruise trim
CG should be such that 0-2 units nose down trim is required for level flight. CG should be 30-33?
3 Eng drift down
Process
Rough estimate
Set MCT
Capture M0.74
Check kneeboard
Notify ATC of required lvl
GW 260k, FL 275
GW +10k, -1,250 ft
Eg. 240k, FL302
Optimal cruise altitude 4 Eng
Approx
GW + FL = 610
Eg. 260klb = FL350 (FL 347)
Endurance Altitude and speed
Ref: 260klb FL260 250kts
+10klb GW = -1000ft, +5kts
