On the Record: RV-4—Idaho

April 6, 2018

During landing, the airplane bounced, and the pilot added power. The airplane landed on the runway, but the left side of the airplane dropped to the ground. The airplane exited the left side of the runway, where it came to rest. The airplane sustained substantial damage to the horizontal stabilizer.

The FAA safety inspector who examined the airplane reported that the weld on the left main landing gear axle support strut had failed with some signs of overload.

NTSB Report.

Ron Wanttaja
Ron Wanttaja
Ron Wanttaja is a retired space systems engineer. During a 40-year career, he helped design, build, test, launch, and operate 18 spacecraft, including the International Space Station. On the aviation side, he has owned a Bowers Fly Baby since 1996 and flew the original prototype for seven years before acquiring his own. He lives just outside of Portland, Oregon, with his wife, romance novelist Lisa McAllister.

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Tom Waarne
Tom Waarne
16 days ago

It hurts just looking at the photos.

Finn
Finn
15 days ago

“Axle support rod” on an RV-4??

Bill B
Bill B
15 days ago

It looks like the weld had been cracked for quite awhile.

Leo K
Leo K
15 days ago

Sorry to see this.
Is the report correct, it lists the plane as a RV-4 Retractable gear tailwheel.

Ron Wanttaja
Reply to  Leo K
15 days ago

If you do an image search on the accident plane’s N-Number (N66PB) you’ll see what is, indeed, a retractable-gear RV-4.

I believe the aircraft was originally built in Canada; I shot of picture of it with Canadian registration back in the ’90s. One of the photos on the online search shows the airplane with the US registration number, though, by the time the accident occurred, it apparently had been repainted.

Might explain the “axle support rod,” too….

Leo K
Leo K
Reply to  Ron Wanttaja
15 days ago

That makes it more sad. Such a rare and cool bird.
And I agree, I think that probably explains the axle support rod.

John Bright
John Bright
Reply to  Leo K
15 days ago
TV
TV
15 days ago

Looks like it failed where the oleo cylinder mounts to the fork? Overload failure, sure, but the visible welds at the top of the photo sure don’t look like they had complete root penetration to the strut tube mounting boss, and they’re a bit discolored. Do RV4 RGs use repurposed, professionally fabricated MLG assemblies or are the forks DIY fabrications?

Last edited 15 days ago by TV
Ron Wanttaja
Reply to  TV
14 days ago

I believe the retract system was a one-of, not a commercial product. One report online said that the performance increase wasn’t that much.