The P-51 Bailout
Another week, another warbird lost—this time, a P-51 involved in a mid-air at the Duxford Flying Legends show in the UK. Watching the video made me wonder if that Skyraider pilot is gonna get an earful about rolling into a turn and losing sight of the P-51. I'll let the warbird guys figure that one out—they've certainly got good video for the post-accident probable cause.
What I found most interesting was the video of the bail out sequence. I'm sure the pilot, Rob Davies, thought hard—but not long—before tossing the airplane and saving himself. In his post-accident interview, he didn't say what the P-51's control issues were and I'm not sure from the video what part came off the tail, but I'd guess the elevator or maybe control cables, so without pitch control, the airplane was headed downhill with no way to right it. His options were down to one.
Davies said he made the bailout decision at about 500 feet and got a good canopy at 200 feet. That sounds low and it is, but emergency parachutes are designed to open almost instantly, so it's no surprise he survived. But I give him a tip of the hat for exiting under duress and, at least according to the video, maybe getting perfect body position before deploying. "Perfect" means belly to earth and stable, not tumbling.
At least I think it's perfect. Scroll to 0:47 in the video. (We've got it queued up for you at right.) Which end is his head? Is he on his back with legs to the right? Or is that his head on the right? I can interpret it either way. Back-to-earth deployments aren't ideal because the pilot chute snakes up either between your legs or from either side of your body. This increases the likelihood of a type of malfunction known as a horse shoe, with the canopy or lines snagged on your feet. That probably wouldn't be survivable. Unstable deployments with round canopies can also cause another type of malfunction: a line over or what's called a Mae West. Not good, but at least you'd have a mostly inflated canopy above your head. So in an emergency bailout, a pilot has to make a decision: Is waiting a beat or two to get stable and giving up some altitude worth the exchange for the higher chances of avoiding a malfunction? After all, you get only one chance at this. I suspect most pilots who aren't skydivers would be happy to just exit the airplane, find the handle and pull it.
When I was a neophyte skydiver some years ago, I was in a Cessna 182 with two others when the engine sputtered on takeoff at about 1000 feet. The door was open and the pilot didn't hesitate: he kicked us out of the airplane. From 1000 feet, the first three seconds are freebies—you have as much forward velocity as downward travel so you fall about 130 feet in that interval. That's enough time to think about getting stable and, in my case, decide whether to use the reserve—which is marginally more reliable—or the main. Also, falling through that first three seconds gives you another advantage: more airflow to pull a pilot chute clear of your back. At slow deployment speeds, it can get stuck in the burble on your back and stay there for many seconds. Decisions, decisions. I went for the main and once I was under it, I heard the airplane motoring back to the airport with a perfectly normal sounding engine. I walked back through a half mile of six-foot corn.
Davies said he was under canopy for about two seconds and had a high rate of descent. The video suggests closer to six seconds, in which case he had about all of the deceleration he was going to get. Round canopies have little forward movement so the descent is a pleasant float—until the last 20 feet. The ground comes up fast and the landing can be harsh. Not many skydivers pine for the days of round canopies. We survived them because we were young and stupid. (Yeah, I know, age hasn't fixed the stupid part. I've heard the joke.)
But this is distinction you wouldn't be making if you were trying to separate yourself from a doomed airplane.