Quid,
Although the FAR’s haven’t changed, its interesting to note how the interpretation of them has. Our older B747’s and the L1011 which
411A flew had a basic contaminated runway correction of
reduce RWY LWT by 10% and V1 by 15 kts . This wasn’t very scientific, but it went someway towards acknowledging the effect of the reduced friction between the aircraft tires and runway. Even though this wasn’t required by the FAA.
With newer aircraft and the computing abilities that came with them combined with directions in the form of FAA AC-91-6B, we were in a better position to judge how we wanted to operate off contaminated runways. Interestingly, while we were just reducing 10% off the RWY LWT for ICY runways, we ended up prohibiting operations from them due to the ineffective braking action. (Wet Ice gives a braking action of 0.05 to NIL).
It amazes me that 10 years after the first issue of AC91-6, it still hasn’t found its way into the FAR’s.
M&V states
the ATA(fleet owners)won't compromise on the payload. I guess that as sad as that sounds, it’s true!
M&V The data available from Boeing for FAA operators is based on FAA AC-91-6B, while this doesn’t directly address the screen height of 15 feet, it was adopted in the advisory data of the time. Therefore you will find that AC91-6B and JAROPS1 are almost the same.
For most modern aircraft, the data is available, therefore IMHO, regardless of the requirements of the FAR’s, any operator who ignores corrections for contaminated runways is grossly negligent.
Mutt.
