Class A Contiminated R/ys

Question 1

A r/y is contaminated when

Answer 1

3 mm of standing water/snow/ ice etc

And

25% of the r/y is covered

Question 2

Contaminated r/y regulation class A

Answer 2

Class A is okay to t/o from contaminated r/ys but national bodies can set regs

CAA prohibits t/o + l/d from a contaminated r/y with

• a tailwind
• Greater than 15mm or water, slush or wet snow or 80mm of dry snow

Question 3

Recommended t/o crosswind strength with contaminated r/y

Answer 3

Recommended 10kts crosswind

Question 4

3 types of hydroplaning

Answer 4

Dynamic
Viscous
Reverted rubber

Question 5

Dynamic hydroplaning

Answer 5

Contamination under the tyres is not displaced enough - tyre is no longer in contact with the r/y surface

Vp = 9 x square root of the tyre psi

Impingement drag disappears above Vp

Higher the tyre pressure, the more aquaplaning

Question 6

Viscous hydroplaning

Answer 6

A build up of rubber, oil, grease on the r/y cant adversely effect braking actions if they become wet

“Slippery when wet” airfields

Question 7

Reverted rubber

Answer 7

As the a/c compresses the water underneath the tyre and gets super heated - turns to high pressure steam - burns the rubber

Question 8

The effect on de-icing on class A t/o

Answer 8

Does not effect V1 speeds

A/c is heavier - margin between V2 and 1.13 Vs is smaller

Question 9

The effect of faulty anti skid on class A L/d

Answer 9

You will need to delay the braking until you are below the Vp speed

Can t/o without anti skid working