21 Additional Take-off techniques

Question 1

Purpose of increased V2?

Answer 1

Improved climb. A higher CLTOM

Move closer to the speed for excess thrust, closer to Vx.

Question 2

V2 for heavier mass?

Answer 2

Question 3

Drawbacks of improved climb technique?

Answer 3

A larger Vr is needed, may cause problems getting close to or eceeding V_TYRES.

Question 4

Purpose of flex thrust take off?

Answer 4

Increase engine life and reliability while reducing maintence and operating costs, and reduce noise.

Question 5

How is thrust reduced take off setup?

Answer 5

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%.

Question 6

At temperatures hotter than the flat rating cut-off, what happens to TOGA?

Answer 6

TOGA thrust reduces with an increase in ambient air temperature

Question 7

Dangers for using flex?

Answer 7

• Excessive low flex thrust used
• Commence take off run from a point way down the runway.

Question 8

Reduced thrust take off is not used when:

Answer 8

• Icy or slipery runways.
• Contaminated runways
• Anti-skid unserviceable
• reverse thrust unserviceable
• increased V2 procedure
• The PMC off.
• Windshear likly.

Question 9

What is de rate thrust?

Answer 9

Setting a new maximum thrust value. This cannot be overridden by pushign throttles to TOGA.

Useful if you want to reduce Vmcg.

Question 10

Graph showing de rate thrust?

Answer 10

Question 11

Dry Runway?

Answer 11

A runway the surface of which is free of visible moisture and not contaminated within the area intended to be used.

Question 12

Wet Runway?

Answer 12

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.

Question 13

Slippery Wet runway?

Answer 13

This is a wet runway where the surface friction characteristics of a significant portion of the runway have been determined to be degraded.

Question 14

Area Intended to be Used?

Answer 14

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.

Question 15

Contaminated Runway?

Answer 15

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

Question 16

How is friction coeffcient attained?

Answer 16

The friction coefficient of a runway may be either estimated, or measured using a continuous friction measuring device.

Question 17

Surface friction catogories?

Answer 17

Estimated surface friction is described as either being good, medium to good, medium to poor or poor.

Question 18

Braking coeffcient values?

Answer 18

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.

Question 19

Wind limitations for contaiminated runways where are they found?

Answer 19

Wind limitations may apply in case of contaminated runways. Those limitations are to be found in Part B of the Operations Manual — Limitations.

Question 20

Where are contaminated runway procedures found?

Answer 20

The procedures associated with take-off and landing on contaminated runways are to be found in Part B of the Operations Manual — Normal procedures.

Question 21

Where are contaminated runway performance found?

Answer 21

The performance associated with contaminated runways is to be found in Part B of the Operations Manual — Performance.

Question 22

Dynamic Hydroplaning?

Answer 22

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.

Question 23

Dynamic Hydroplaning velocity for a rotating tyre?

Answer 23

Rotating Tyres formula (applies to rejected take-offs)

Question 24

Dynamic Hydroplanning for a locked-up non rotating tyre?

Answer 24

NON-Rotating Tyres formula (applies to touchdown)

Question 25

Viscous Hydroplaning?

Answer 25

Viscous hydroplaning can result from an excessive build-up of rubber on the runway surface. The tyres hydroplane on the partially melted rubber lying on the runway surface.

Question 26

Reverted Rubber Hydroplaning?

Answer 26

Reverted rubber hydroplaning occurs when a wheel locks on a damp or wet runway. The superheated tyre generates high-pressure steam. This causes the surface rubber to revert to its uncured state, resulting in a hot fluid layer building up between the tyre and the runway surface.

Question 27

Minimum Speed?

Answer 27

The minimum dynamic hydroplaning speed for a rotating tyre is 9 root P. For a locked-up tyre it is 7.7 root P. The higher value is most likely to be the most limiting on take-off. The lower value may be a factor on landing before wheel spin-up.

Question 28

EFB data?

Answer 28

EFB data can differ slightly from tabled data because the electronic databases contained in EFB software programmes contain greater data granularity.

Question 29

Slush?

Answer 29

Water-saturated snow which with a heel and toe slap-down motion against the ground will be displaced with a spatter.

Will increase TOD and ASD.

Question 30

Dry snow?

Answer 30

Snow which can be blown if loose or, if compacted by hand, will fall apart again upon release.

Question 31

Wet Snow?

Answer 31

Snow which, if compacted by hand, will stick together and tend to form a snowball.

Question 32

Compacted snow?

Answer 32

Snow which has been compressed into a solid mass that resists further compression and will hold together or break up into lumps if picked up.

Does not increase or reduce take off run, and increases landing run

Question 33

The end of the OEI take off run?

Answer 33

The middle of the segment between Vlof and 35ft

Question 34

The effect if taking of at a higher airport on V2min?

Answer 34

At high air density airport engine thrust would be higher, therefore in case of engine failure the effect of assymetric thrust is more pronounced. This increase VMCA which would increase V2MIN too.

Question 35

Are line up losses considered in declared take off distances available?

Answer 35

The length of the runway that is declared for the calculation of TODA, ASDA and TORA does not account for line-up of the aeroplane in the direction of take-off on the runway in use. This alignment distance depends on the aeroplane geometry and access possibility to the runway in use. Accountability is usually required for a 90°-taxiway entry to the runway and 180°- turnaround on the runway.