Question about the torque on a 737's engine mount bolts

I was reading an old maintenance manual from the 90s for a 737-300 and saw the torque spec for the engine mount bolts. It said 450 foot-pounds, which just seemed huge to me. I had to double-check it with a senior mechanic who confirmed it. He said the shear loads during a hard landing or turbulence are way bigger than you'd think. Has anyone else been surprised by a torque value they found in an old manual?

3 comments

3 Comments

evan_wilson188d ago

The manual's margin notes warned about bolt stretch at that torque.

caleb_ross1212d ago

Yeah, 450 foot-pounds is a monster. I once spent twenty minutes looking for a torque multiplier because I misread a spec for a simple bushing bolt. Turns out it was 45 inch-pounds, not foot-pounds. My pride still hasn't recovered from that one.

derek99412d ago

Wait, you misread inch-pounds for foot-pounds? That's a huge difference, man. I'd be triple-checking every number in that manual after a mistake like that.