Teflon Tape Friend or Foe Teflon tape is the plumbers friend I have used it many times to stop an annoying leak in air line fittings So why not use it to stop leaks on aircraft hydraulic and oil lines? Read on and well see why it is NOT a friend when used on aircraft systems#1.Advances Automatically

Teflon Tape Was the CulpritOne Person Died in this Aircraft#2.

So What Happened?The pilot took off with a full load of loggers on their way homeThe gravel airstrip was located up a narrow valley with the river along side of it making it a one way in and one way outEverything seemed normal until just after the gear was retractedThe left engine suddenly lost power and the aircraft swung wildly toward the left mountain sideHe straightened the aircraft and adjusted the trim for the power lossSuddenly the power came back on stronger than before causing the aircraft to swing violently toward the right mountain sideEven with full opposite rudder the aircraft was still heading for disasterNot knowing what was happening but knowing that if this kept up they would all die, he Cut the power and belly landed in the riverOne person would not get out of the aircraft aliveWhat Caused the Engine Surges?#3

Teflon Tape This tape was found inside the controller for the turbocharger wastegate The tape had plugged a critical orifice and than squeezed through This had caused the engine to suddenly lose than gain power #4.

Teflon Tape Tape after squeezing through the calibrated orifice So how did it get there?#5.

So how did it get there?An AME had just recently replaced a pipe thread fitting into the controller BUT he had not used teflon tapeBut the person before him hadSmall strips of the tape remained in the controller threads until he put the new fitting inThis pushed these almost invisible killers into the oil system above the oil filter and set them in place to cause a fatal accidentFirst Time Something Like This Had Happened?#6

Im Afraid NotA 747, fully loaded, departed Vancouver headed for Hong KongThe one of the main gear would not retract so an emergency was declared and after dumping tons of fuel out over the water it landed without further incidentThe aircraft was taken to the hangar where several retraction tests were carried out without any problemHydraulic filters were changed and after refueling, the load of now nervous passengers boarded for their flightMurphy was alive and well as once more the main gear would not retract in flight and the water was treated to another dose of jet fuelWith the next trip to the hangar came the order dont send it back until you are absolutely sure the gear will function as designedEvery hydraulic component in the main gear was replaced AND#7.

ANDA much smaller number of nervous passengers departed for a normal flight to Hong KongEach removed component was carefully disassembled under the watchful eye of Quality ControlFinally the culprit was found in one of the main landing gear door sequence valvesIt was, you guessed it, a tiny piece of Teflon TapeThat piece of teflon tape had cost them over $1/4 million dollars plus the loss of public confidenceThey went through every toolbox in the hangar looking for the guilty party (Thank goodness I had taken it home Just kidding) Not me thank goodnessDont let it be YOU#8.

Teflon Tape is a Foe to Aviation It can wait a long time before striking If you are lucky, it will only cost money Or it can become a silent killer Dont give it a chance to strike

DO NOT USE TEFLON TAPE ANYWHERE NEAR AN AIRCRAFT OR ITS COMPONENTSGordon Dupont#9Have a Safe Career