The Pre-inspection Run-up

FAA regulations require post-inspection run-ups to verify proper operation of power plant system after inspections, servicing and repairs. When performed at the start of the inspection the pre-inspection run-up becomes a valuable tool in properly administering the annual / 100 hour inspection. Properly performed and documented it can help prevent those surprises that seem to manifest them-selves at the end of the inspection process.

First consideration is for the owner / operator to communicate anything he has experienced outside of normally operating parameters so the technician can be on guard for these problems. You will do well to record the incidences as they happen, a progressive history will give your technician valuable diagnostic clues. Written information help prevent misunderstandings between maintenance and operators.

Over the years we have developed our own pre-post run-up form which is a single page of single spaced lines which document the information we most need without being too cumbersome. For the most part is arranged in logical order.

One of the things we do is prepare the aircraft for the run-up. If there are large or numerous oil leaks we will clean so as to give us a chance in finding the source. Following diagnostic equipment is then installed:

A. Accurate volt meter for additional monitoring of the electrical system

B. Vacuum gage for those aircraft only having indicator lights

C. Pressure gage calibrated in inches of water attached with hose to the oil filler neck to measure engine case pressure. (TCM SB 89-9)

D. Metered / un-metered fuel gages for TCM fuel injected engines if pressures are in doubt.

E. Hydraulic pressure gage for those aircraft with engine driven pumps and no installed gage

F. Direct reading oil pressure gage if indications or oil pressure are suspect

G. Direct reading fuel pressure gage if indications or fuel pressure are suspect.

H. Air conditioning gages

A hand held photo tach is placed on board to check tach accuracy.

Brief inspection of the engine compartment and the aircraft are conducted at this time so as not to cause any damage during the run-up.

Before starting the engine(s) the master switch is turn on and the engine gages’ static readings are observed. Quite often we will discover gages that do not return to zero on shut down.

During starting the voltmeter is observed for low voltage which could

indicate possible battery or starter problems.

The following items are checked and recorded during taxi and run up:

Ignition switch safety check

Com / transceiver check

Clock / timer / chronometer

Hour meter operation

Outside air temp

Atis identifier / barometric setting

Altimeter indicated altitude compared with field elevation

Brakes / parking brakes

Ground steering

Wheel balance

Oil pressure idle / cruise

Oil temperature

Cylinder head temperature(s)

Fuel pressure / flow, idle / cruise

Primary alternator / generator (DC & AC)

Standby / #2 alternator / generator (DC & AC)

Primary / standby voltage regulator

Magneto operation / drops

Propeller response

Vacuum / gyro air pressures, primary / stand-by / #2 :

Engine controls

Throttle, mixture, prop, carburetor heat / alternate air, cowl flap(s), turbo

Carburetor air temperature

Hydraulic pressure

Tach calibration check

Exhaust gas temperature(s)

Turbine inlet temperature

Compressor discharge temperature

Static power, max rpm / manifold press / fuel pressure / flow :

Crankcase pressure, cowl flaps open, closed (at full static power)

Idle mixture rise / idle rpm / cut-off

Flight director / gyro horizon

Horizontal situation indicator / direction gyro

Turn coordinator / turn & bank

Compass / remote indicating compass

De-ice

Surface, windshield, prop de-ice

Propeller feather / un-feathering

With all the above out of the way and recorded it is time to taxi back to the hanger and start the compression checks.

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