Ask Captain Lim

Hi Capt Lim,

I have two general questions which are not very technical.

Hope you are happy to answer it.

1) In Cessna we have a Turn Coordinator to give Slip and Skid indications of the aircraft. Where is this information found in the Boeing 777 flight deck?

2) Assume I know the definitions of CAS, TAS, GS and MACH Number, I sometimes see CAS (Calibrated Air Speed) and sometimes in OPT CRZ (Optimum Cruise), MACH Number is used. So when is CAS and when is MACH Number indicated in flight on the Boeing 777?

Please let me know.

Thanks

Srihari J

Hi Srihari,

The information for the Turn and Slip Coordinator is incorporated into the Primary Flight Display and the cut off point between the CAS and Mach Number is when the Boeing 777 passes through around 31,000 feet. It automatically changes from CAS to Mach Number at this level in the Climb or Descent.