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PTO Sheering at the AMAD

Unread postPosted: 21 Aug 2017, 21:51
by juvat67
Has anyone heard of AMADs in the aircraft sheering the PTO shafts? So far I have heard of potentially six. Is there a trend going on?

Re: PTO Sheering at the AMAD

Unread postPosted: 22 Aug 2017, 01:10
by quicksilver
What's an AMAD? What's a PTO?

Re: PTO Sheering at the AMAD

Unread postPosted: 22 Aug 2017, 03:03
by johnwill
On F-16, Airframe Mounted Accessory Drive (generators, hydraulic pumps, etc.) driven by a Power Take Off shaft from the engine.

Re: PTO Sheering at the AMAD

Unread postPosted: 12 Sep 2017, 19:26
by lowandslow
Any update on this issue?

Re: PTO Sheering at the AMAD

Unread postPosted: 13 Sep 2017, 08:31
by 35_aoa
I'm sure the old guys around here will confirm or correct this, but my understanding is that it was a problem that happened a number of times in the old days of 200/220 motors, and was engineered out of later build 220 and 229 motors. Not sure if there is truth to that, but the old guy who ran our F-16 indoc/training program for a while said he hadn't heard of it happening for many years.

Re: PTO Sheering at the AMAD

Unread postPosted: 19 Sep 2017, 03:01
by That_Engine_Guy
35_aoa wrote:I'm sure the old guys around here will confirm or correct this, but my understanding is that it was a problem that happened a number of times in the old days of 200/220 motors, and was engineered out of later build 220 and 229 motors. Not sure if there is truth to that, but the old guy who ran our F-16 indoc/training program for a while said he hadn't heard of it happening for many years.


Hence the "PTO Shaft Run-out" Check that needed to be performed on the F100 engine PTO mounts.

Earlier PTO mounts on the Engine Gearbox would become 'worn' and could 'wobble' while being driven; the excessive motion would cause the PTO shaft undue stress and it would fracture at it's shear point. (The shaft was designed to break and contain it's self in the event the airframe gearbox seized, it would not seize the engine gearbox, or vise versa)

A duplex bearing was installed in the shaft on the F100 so that the wear would be minimized/eliminated, but the check is still done during JEIM visits to ensure there is no excessive play.

Keep 'em flyin' :thumb:
TEG