Broken Mustangs

Fans of aviation and the families of the dead and injured are mourning the September 16, 2011 crash of Jimmy Leeward's Galloping Ghost at the National Air Races in Reno, Nevada. Ten were killed including Leeward, and some seventy were injured.

I stress: Nobody knows the cause of the crash, and everything in this blog post is my own personal speculation.

The media has described Leeward's plane as a "vintage" plane. This is hardly true. While WWII-era P-51 Mustangs, like Galloping Ghost, have long been mainstays of the Unlimited class in which he was competing, there is hardly a component of the original planes remaining. These planes are as fast and as modern as anyone knows how to make them. They are the fastest piston-driven airplanes in the world, and no expense is spared to gain a fraction of a knot in airspeed. Each is unique and is built to the extreme.

Attention focused early on a photograph of the tail of Leeward's plane, showing a damaged trim tab on the elevator. This has happened to Mustangs before at Reno. In 1998, Bob Hannah was flying the P-51 Voodoo in a heat race and an elevator trim tab came off, causing an abrupt pitch-up which resulted in a 10 G deceleration that knocked Hannah unconscious. Fortunately he was able to land safely. Superficially, the situation appears very similar to what happened to Leeward.

Aerodynamic forces are probably to blame for both breakages. When airplanes approach the speed of sound (Leeward and Hannah had both been traveling about Mach .67), airflow over certain parts of the airframe will exceed the speed of sound and create shockwaves.These can be like hitting the airplane with a hammer. They cause buffeting and damage.

Other photos show that Leeward's tailwheel, which is normally retracted for racing, was extended. It's possible that there was damage affecting multiple systems on the plane, but it's perhaps more likely that the wheel could have popped out from a sudden high G load.

Leeward was able to radio a mayday call, alerting others to his problem, (Update - the NTSB said in its briefing that no mayday call was made, which makes more sense) but one photo of the plane just before its crash shows his helmet apparently leaning all the way forward against the controls. Leeward was 74 years old, and though he flew his Mustang at the edge of its performance envelope often, a 10 G shock might have knocked him out as it had to Hannah. At this time, nobody knows the order of events: the breakage to the trim tab, the mayday call, the extension of the tailwheel, and any potential aerodynamic force event.

It's a major bummer for everyone involved. Hopefully this accident won't impact the future of the race, but that's another discussion for another time.