Jaba W. As much as I admire John Deakin's "Pelican's Perch" engine handling series, I must say I am surprised when he said that run up procedures should be conducted with the park brake off and holding on the brakes by pedal pressure alone.
His article states:
Set the Brakes?
A very strong "No!" answers this question, for those airplanes with anything but power brakes.
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If Deakin's technical argument for not using the park brake when stopped is valid, then it would suggest the aircraft certification process is flawed.
While I have often see pilots conduct run up's using brake pedal pressure only, it is an unwise policy in general; especially at night or in heavy rain where it is sometimes difficult to pick movement of the aircraft inching forward or on a rear sloping surface moving backward.
The most common reason for some pilots not using the park brake in general aviation aircraft is that from the beginning of their ab-initio training they are taught by their instructors not to trust the parking brake. This is negative teaching. It stems possibly from another fact in general aviation and that is many pilots are reluctant to write up defects in the maintenance release for fear of management or aircraft owner adverse reaction.
A pragmatic reader can understand why some pilots are wary of using the park brake for run up's. Good airmanship would dictate that until you are sure the park brake is holding correctly at high power, it is wise to be ready to apply prompt brake pedal pressure if the aircraft begins to move. But don't forget to promptly close the throttles.
If the park brake is inoperative or not holding, then legally you are bound to write it up in the maintenance release. If the defect is not cleared before the next flight, at least the next pilot is aware when he studies the maintenance release before flight. Too many pilots are happy to let the next pilot wear an unreported defect with the callous attitude of `not my problem mate`and let the next bloke carry the can.
In the POH for the venerable Cessna 172 the manufacturer's checklist states that before starting the engines "Brakes ---TEST and SET". The Securing Airplane checklist states "Parking Brake---SET".
During a run up, holding on the brake pedals rather than setting the parking brake, it only takes a momentary lapse of concentration to inadvertently relax one or both feet from the pedal pressure; particularly if heads down events are taking place in the cockpit such as writing down clearances or briefings. The parking brake is good insurance. In event of an incident involving the non-use of the park brake when it should have been on, the lawyers would have a field day citing the manufacturer's POH.
Last edited by Tee Emm; 8th Jul 2016 at 07:19.