21 Additional Take-off techniques Flashcards
Purpose of increased V2?
Improved climb. A higher CLTOM
Move closer to the speed for excess thrust, closer to Vx.
V2 for heavier mass?
Drawbacks of improved climb technique?
A larger Vr is needed, may cause problems getting close to or eceeding V_TYRES.
Purpose of flex thrust take off?
Increase engine life and reliability while reducing maintence and operating costs, and reduce noise.
How is thrust reduced take off setup?
Thrust is reduced by entering a artifically high ambient temperature higher then Tref into the FMC. This fools the FMC into beliveing that conditions are hotter then they are.
This reduces the calcualted TOGA upto a maximumm of 25%.
At temperatures hotter than the flat rating cut-off, what happens to TOGA?
TOGA thrust reduces with an increase in ambient air temperature
Dangers for using flex?
- Excessive low flex thrust used
- Commence take off run from a point way down the runway.
Reduced thrust take off is not used when:
- Icy or slipery runways.
- Contaminated runways
- Anti-skid unserviceable
- reverse thrust unserviceable
- increased V2 procedure
- The PMC off.
- Windshear likly.
What is de rate thrust?
Setting a new maximum thrust value. This cannot be overridden by pushign throttles to TOGA.
Useful if you want to reduce Vmcg.
Graph showing de rate thrust?
Dry Runway?
A runway the surface of which is free of visible moisture and not contaminated within the area intended to be used.
Wet Runway?
A wet runway is defined as a runway the surface of which is covered by any visible dampness or water up to and including 3 mm deep within the area intended to be used.
Slippery Wet runway?
This is a wet runway where the surface friction characteristics of a significant portion of the runway have been determined to be degraded.
Area Intended to be Used?
The area of the runway that is part of the TORA, ASDA or LDA, as declared in the aeronautical information publication (AIP) or as notified by NOTAM.
Contaminated Runway?
A runway is contaminated when more than 25% of the runway surface area is covered by greater than 3 mm of water or its equivalent depth in slush or loose snow, or compacted snow or ice
How is friction coeffcient attained?
The friction coefficient of a runway may be either estimated, or measured using a continuous friction measuring device.
Surface friction catogories?
Estimated surface friction is described as either being good, medium to good, medium to poor or poor.
Braking coeffcient values?
Measured surface friction is given as a numerical coefficient. 0.40 and above means the expected braking action is good. Anything below 0.25 means the expected braking action is poor.
Wind limitations for contaiminated runways where are they found?
Wind limitations may apply in case of contaminated runways. Those limitations are to be found in Part B of the Operations Manual — Limitations.
Where are contaminated runway procedures found?
The procedures associated with take-off and landing on contaminated runways are to be found in Part B of the Operations Manual — Normal procedures.
Where are contaminated runway performance found?
The performance associated with contaminated runways is to be found in Part B of the Operations Manual — Performance.
Dynamic Hydroplaning?
Dynamic hydroplaning occurs when the contamination under the tyres is not displaced fast enough to allow the tyre to make contact with the runway surface over its total footprint area.
Dynamic Hydroplaning velocity for a rotating tyre?
Rotating Tyres formula (applies to rejected take-offs)
Dynamic Hydroplanning for a locked-up non rotating tyre?
NON-Rotating Tyres formula (applies to touchdown)
