Teflon Tape Friend or Foe Teflon tape is

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

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

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the river along side of it making it a one way in and one way out • Everything seemed normal until just after the gear was retracted • The left engine suddenly lost power and the aircraft swung wildly toward the left mountain side • He straightened the aircraft and adjusted the trim for the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

Teflon Tape v This tape was found inside the controller for the turbocharger wastegate v The tape had plugged a critical orifice and than squeezed through v. 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 tape • But the person before him had • Small strips of the tape remained in the controller threads until he put the new fitting in • This pushed these almost invisible killers into the oil system above the oil filter and set them in place to cause a fatal accident First Time Something Like This Had Happened? #6

I’m Afraid Not q A 747, fully loaded, departed Vancouver headed for Hong Kong q The 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 incident q The aircraft was taken to the hangar where several retraction tests were carried out without any problem q Hydraulic filters were changed and after refueling, the load of now nervous passengers boarded for their flight q Murphy 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 fuel q With the next trip to the hangar came the order – don’t send it back until you are absolutely sure the gear will function as designed q Every hydraulic component in the main gear was replaced AND #7 .

AND • A much smaller number of nervous passengers departed for a normal flight to Hong Kong • Each removed component was carefully disassembled under the watchful eye of Quality Control • Finally the culprit was found in one of the main landing gear door sequence valves • It was, you guessed it, a tiny piece of Teflon Tape • That piece of teflon tape had cost them over $1/4 million dollars plus the loss of public confidence • They went through every toolbox in the hangar looking for the guilty party (Thank goodness I had taken it home – Just kidding) • Not me thank goodness #8 Don’t let it be YOU .

Teflon Tape is a Foe to Aviation ü It can wait a long time before striking ü If you are lucky, it will only cost money ü Or it can become a silent killer ü Don’t give it a chance to strike DO NOT USE TEFLON TAPE ANYWHERE NEAR AN AIRCRAFT OR ITS COMPONENTS Have a Safe Career #9 Gordon Dupont