in-flight trouble shooter

General Troubleshooting

  •   Check the aircraft breaker or fuses. Reset once only.

  •   Is electrical system properly charging?

  •   Could water have leaked onto the avionics?

  •   Could a connector be loose or wire broken from recent maintenance?

  •   Do you hear alternator or mag noise?

  •   Are any antennas missing, corroded, dirty, broken, oil coated, delaminated?

  •   Is the problem intermittent?

  •   Could heat, cold, altitude or time be a factor?

Com/Audio Panel/Intercom

  •   Is the correct frequency active (not standby)?

  •   Are the audio switches set correctly?

  •   Is the auto mode being used?

  •   Is the same radio selected for transmit & receive?

  •   Is the volume turned down?

  •   Is a mic key stuck?

  •   Are both the headphone and speaker working?

  •   Does it both receive and transmit?

  •   Do you hear your voice in headphone during transmit (sidetone)?

  •   Did ATC say they heard carrier only without voice?

  •  Is there background noise when in test mode (squelch off)?

  •   Try a different headset or microphone.

  •   Try emergency or isolation modes.

  •   Are the plugs or jacks dirty, corroded or loose?

  •   Do all crew & passenger headset locations have the same problem?

  •   Does another com act the same?

  •   Is oxygen mic. switch in proper position?

Autopilot

  •   Review operating procedures.

  •   Does it pass self-test on the ground?

  •   Does the autotrim work?

  •   Does the manual electric trim work?

  •   Does it engage?

  •  Can you overpower it on the ground?

  •   Do the controls lock when engaged?

  •   Could the cables be loose from maintenance?

  •   Is the aircraft out of trim?

  •   Is the horiz gyro precessing?

  •   Is gyro vacuum within limits?

  •   Does it hold the wings level?

  •   Does it hold heading?

  •   Do the wings rock?

  •   Does it respond in basic pitch hold?

  •   Does it hold altitude?

  •   Does it lose altitude in a turn?

  •   Does it porpoise?

  •   Does it respond in NAV?

  •   How does it respond on an ILS?

Transponder

  •   Is ATC receiving both Mode-A (squawk code) and Mode-C (altitude)?

  •   Has the problem occurred with more than one ATC facility?

  •   Is Mode-C inop, or just reporting wrong altitude?

  •   Does the reply lamp illuminate in radar coverage?

  •   Is the reply lamp dimmer turned down?

  •   Is it in the correct mode (standby/on/alt)?

  •   Does it recycle (power off, then on, then wait 30 seconds)?

  •   Does test position illuminate reply lamp?

  •  Does turning off the DME resolve the problem?

DME

  •   Does it receive an ident code? (Listen for 60 seconds)

  •   Is the remote channeling switch set?

  •   Is the display dimmed?

  •   Does the GS and TTS function? (Flying directly to/from but not over station.)

  •   Is problem present on other frequencies?

  •   Does it test?

  •   Is there a NOTAM of any outages?

ADF

  •   Is it on the correct frequency?

  •   Is the unit in ADF mode?

  •   Does it point to the station?

  •   Does the needle move in test?

  •   Does the unit receive in ANTmode?

  •   Does the unit receive in ADF mode?

  •   Do all three frequency bands work—(200-399, 400-799, 800-1699)?

  •   Do you hear alternator or mag noise?

  •   Is the reception better on the ground with the engine off?

  •   Are other radios interfering with the ADF?

  •   Are there thunderstorms in the area?

  •   Is there a NOTAM of any outages?

GPS

  •   Verify the correct waypoint.

  •   Check present position or nearest airport.

  •   Are at least three satellites being tracked (VFR), four satellites (IFR)?

  •   Is the satellite geometry poor?

  •   Are the satellite signal levels adequate?

  •   Has the unit been inactive for a few months?

  •   Is the hold or OBS mode selected?

  •   Is the NAV selected to an ILS frequency locking out course indication?

  •   Is there a NOTAM of any outages?

  •   Are there any warning or error messages?

  •   Does it have the latest hardware/software updates?

VOR/ILS

  •   Is the correct frequency active (not standby)?

  •   Does it receive the ident code?

  •   Do the needles or flags move at all?

  •   Can you select a reciprocal OBScourse?

  •   Does the To/From indicator work?

  •   How many degrees off is the VOR?

  •   Does the NAV test (self or VOT)?

  •   Does it have 20° course width peg to peg?

  •   Do both NAVs have the same problem?

  •   Does the Localizer work but not the VOR?

  •   Are you close or far from the station?

  •   Does a change in engine rpm have an effect?

  •   Is the RNAV or PAR mode active?

  •   Is the Loran/GPSswitched to the indicator?

  •   Is there a NOTAM of any outages?

  •   Is problem present on different frequencies?

  •   Does VOR station position relative to aircraft have an effect?

Marker Beacon

  •   Do the lamps illuminate over markers?

  •   Do lamps test?

  •   Are the lamps dimmed?

  •   Is problem resolved when high sensitivity selected?

  •   Is the audio turned down or not selected?

  •   Are lights seen but tones not heard?

  •   Are the correct tones heard?

Radar

  •   Does it paint rain and ground clutter?

  •   Is the gain turned down?

  •   Is the brightness turned down?

  •   Does it test?

  •   Does it display wheel spokes?

  •   Does the tilt work?

  •   Are the images smeared?

  •   Does it lose targets within 40 miles?

  •   Is the radome damaged or delaminating or leaking?

  •   Is stabilization working?