That time an MD-80 engine change taught me to double check EVERY torque value

I was out on the line at O'Hare last winter doing a QEC swap on a Pratt 5000 series and one of the senior mechanics pulled me aside after I torqued the B-nuts. He showed me how a .5 inch extension in the wrong spot can throw the whole sequence off by 15-20% on a critical clamp. Anyone else ever get burned by trusting the book data without checking the tool setup first?

3 comments

3 Comments

fiona_kim972d ago

I agree with the takeaway but that 15-20% number might be a bit high for a standard extension in good shape. A half inch wobble extension on a typical click style torque wrench can shift the reading by maybe 5-10% depending on the angle and fastener size. Still a good reminder to always test your tool setup on a known torque checker before going to the airplane.

susan812d ago

HOLD UP. "A .5 inch extension in the WRONG SPOT can throw the whole sequence off by 15-20%?" That's absolutely INSANE. I've been wrenching for over a decade and THOUGHT I was being thorough by just checking the torque values in the manual. Now I'm realizing I've probably been off by that much on a bunch of Pratt crap without even knowing it. That kind of difference on a critical clamp could literally cause a fire or a total engine failure. Thank you for sharing this because I'm going to go double check EVERY setup extension from now on. That's the kind of real-world wisdom you don't get from any textbook.

charlies372d ago

Read a really good breakdown on the torque extensions once that showed how even a small off-angle can mess with the final reading way more than people think. Definitely woke me up to checking my setup every time now.