Our Mission: "To assist our clients in developing the best possible Safety System to meet their needs".





"The Price of a Mistake"

Released . 2004

This accident, which happened over 30 years ago, remains vivid in my mind today.

I knew the AME only to see him, but I realize that there, except for the grace of God, go I.  This true story is representative of what we as AMEs/AMTs fear most.

Work out the chain of events and then let’s devise ways that we can ensure that something like this never becomes our worst nightmare.



Produced by  System Safety Services


“We must learn from the mistakes of others

because we will never live long enough

to make them all ourselves”


To purchase, or for more information regarding this case study contact

Gordon Dupont

System Safety Services

Website: www.system-safety.com

Email: dupontg@system-safety.com

Phone/Fax: 604 526-3993

  This case study may be reproduced for use with the training video



When I was a young AME, there was a terrible plane crash that I'll never forget.  The following is the true story as told by the AME who made the one fatal mistake.

Normally I'm a happy go lucky person but that day my world turned upside down.  Grief washed over me in suffocating waves.  The sight of those seven caskets in a grimly accusing row was almost more than I could bear.  I didn't think I could stand it.  I was responsible.  They were dead because of my error.  I was a failure.

I'll never forget the moment I first heard the news.  It was almost suppertime.  Nearly everyone was beginning to unwind after another busy day.  We were wrapping things up at the hangar where I'm an aircraft maintenance engineer. Two planes were still out but would be back before dark.  The flight dispatcher was standing by for their radio calls and heard the call.  He hit me with it cold, when over the phone he said: “The Aztec is on fire.  I raced to the dispatch room in time to hear them desperately dive for safety at Bobqic and crash just short of the runway.  Dave was on his way to Goodhope and saw it from the air.  He said it looked bad.   I couldn’t believe it!  It couldn’t be!  Not our plane!

Dave told us no one survived while I listened in numbed silence.  He was near Bobqic, an abandoned WWII airfield about halfway on the 40 minute run to Goodhope when he heard Don call our dispatcher:  "Mayday, Mayday, Mayday!  I have a fire in my starboard engine and am now feathering.  I'll try for a landing at Bobqic."  Dave spotted the Aztec, streaming frightful orange and white flames from the right engine and a long trail of ugly black smoke traced Don's desperate dive for safety.  The Aztec passed over the runway and was turning to land when suddenly there was a brilliant flash of fire and the right wing folded upward.  The plane rolled violently to the right and crashed inverted.  There were no survivors.  Seven people perished instantly in a ball of flame and twisted metal.

Too stupefied to feel emotion, I sat in a daze.  My thoughts raced around in tortured circles.  Did I do something wrong?  I was one of the aircraft mechanics maintaining the Aztec.  I tried to think, but my mind was numb.  The events of the preceding day were routine.  I had performed a hundred hour inspection as I had done so many times before.  I had inspected the right engine at the end of the day!  The one that caught fire!  That had to be the key.  Was there something I had or hadn't done?

Kyle, a new apprentice had helped me on the inspection.  He was changing the right magneto while I was underneath the engine replacing the carburetor fuel finger screen.  I had just hooked up the fuel line again and twisted the B nut finger tight when he asked for a hand with the mags.  I got out from under the engine to help and.... That had to be it!!  I never finished tightening that nut with a wrench!  I was stunned.  My practice of always making a final visual inspection of everything I do had failed me.  How could I have missed that nut?  The thought was agonizing.  The simple lack of a final twist of the wrench on that fuel line meant a fine spray of gasoline could escape.  It went unnoticed on the post-inspection run-up I'd done late that evening, but after several hours of flying, the nut must have loosened more and then...WHOOSH, Fire!

I turned to Keith, our Chief Pilot, and in the midst of tears and grief, told him it was my fault.  Sure enough, a subsequent investigation by the Dept. of Civil Aviation proved it.  The nut on the fuel line was only finger tight.  My failure to tighten that nut cost seven people, my close friends and co-workers, their lives. I had killed them.

The funeral was a ghastly ordeal.  The sight of those caskets lined up hit me like a blow to the stomach.  I wanted nothing but to get out of there.  At the gravesite the same terrible anguish gnawed at my vitals.  Oblivious to anything but my grief, I was absolutely, totally wretched.  How could I face my friends?  How could I face myself?  I was overwhelmed with guilt.  I was a failure.  The tyranny of that failure made the next few days the worst I've ever lived.  I was responsible for a hundred hourly on one of our other planes.  It was the last thing I wanted to do but there was no choice.  I remember going from the hangar into the parts store to get a new fuel line.  I started to pick it up but couldn't.  I was literally repulsed.  Tears flooded my cheeks; I leaned on the bench and sobbed.  I couldn't do it.  I couldn’t work on planes.  Look what I had just done - sent seven people to their deaths.

Love had got me through that week; the love of Kyle assigned to help with the work.  He sensed the tumult in my mind and encouraged me.  I'm sure that everyone knew something of the cause of the accident but I never sensed rejection by anyone.  But it was not over yet.  The emotional wringer squeezing me dry of everything but guilt and grief still had one more twist before spitting me out.  I wanted to talk with Don's wife but I was afraid.  What would she say?  I couldn't face her so I put it off and the longer I put it off the harder it got.

On the day Don's family was scheduled to return to live with her parents, I was working at the hangar as usual.  They were waiting for the 206 to return from the milk run in the pilot's lounge.  I had to talk to them.  I hesitantly pushed the door open and asked everyone but Angela to leave.  No one spoke; they just got up and left; left me with the wife of the man I had killed.  I closed the door and opened my broken heart.  I wept and wept.  My voice choked with sobs as I asked her for forgiveness.  "That hand there", I said, "took Don's life".   With almost incoherent, sobs shaking my whole body, I sat wrapped in misery.  Angela reached out and took my hand into hers, the hand that had taken her husband's life.  The warmth of her forgiveness flowed over me like a balm.  Time has gone on and the healing continues.


Post Script:

While Charlie, the AME, may be held responsible for the loose B nut and the resulting engine fire, I feel that he was not responsible for the seven deaths, as all aircraft are required to have a safety net in the event of engine fires called a firewall.  This firewall safety net had a large hole in it in the form of an aluminum turbocharger oil tank that had been installed after-market as an approved modification. This approved mod went right through the firewall.  It is believed that it was the oil from this tank that continued to burn even after the pilot had shut off the fuel to the engine.                                                                  



                    Lycoming TIO-540


Sadly, Charlie died about 5 years later of cancer.  I believe that he never forgave himself for the simple error he committed.  That also can be the terrible price of a mistake.

A safety net is often the last chance to stop an error from becoming an accident.