Si Vis Pacem Parabellum

| Friday, October 13 2006 |

Yeeeeaah, I'm gonna have to go ahead and disagree.

Brian says of the recent Lidle crash in Manhattan:

With that in mind, that East River corridor starts to look like a death trap, huh? It's almost as though sooner or later, with walls and ceilings all around you and a restricted-airspace boundary looming up ahead, something like this was more or less bound to happen eventually...

... and that irks, because it echos the hand-wringers who the talking heads have been pushing on the news, who have been vilifying GA pilots and unrestricted airspace around Manhattan.

The east corridor, which I've flown myself, isn't some tiny little thread-the-needle spot in the sky that you need 2000 hours and an F-16 to survive. It's big, nearly half a mile wide with over 1,000 feet of altitude over the river. That's not a small amount of space to fly in, even with other traffic. In fact, several dozen pilots a day have gotten through that airspace for decades with zero incidents. And further, it's airspace. There are no cement walls in place should one dip a wingtip into the restricted airspace that surrounds it. You may, at worst, get a tongue-lashing from the ATC if in an emergency you have to cross into Class B space for some reason.

The media, and NYT graphic Brian links, imply that in order to get into the north side of a building in Manhattan from the east corridor, all one has to do is flip out for a few seconds and yank the stick the wrong way. That isn't the case. The building that Lidle crashed into is nearly a 1/8th mile from the river, and most pilots, even newbies, tend to give themselves a reasonable buffer from both the LGA Class B and "sidewinder up my six" airspace that exists over Manhattan. It takes more than a few seconds to make a 180 degree turn at 100 knots or so, and if in control of an aircraft while doing so, one typically doesn't dive over 500 feet in the space of a minute as Lidle's plane did.

Lidle was flying a Cirrus SR20. These are fast, performance-oriented aircraft. They can turn on a dime and have more than enough power to get themselves out of just about any kind of situation you could imagine.

So, my theory is that there was some kind of drastic mechanical failure with his plane. Either an engine failure combined with inexperience (which is hard to swallow, given a several-thousand-hour instructor on board), or something involving the emergency parachute system found on most Cirrus aircraft, which if accidentally deployed could possibly damage the tail of the aircraft, which could then result in an uncontrolled turn as was what appeared to have been the case in this crash.

I can't say with any certainty what caused Lidle to crash, but I can say with a good deal of certainty that it wasn't inexperience alone, and that the east corridor is a heck of a lot bigger than the talking heads seem to think it is.

Moreover, what really cheeses me off is the knee-jerk reaction out of the media to shut down that airspace, and vilify GA aviators in general. You don't shut down the interstate when someone stuffs their SUV into a median, and there's no reason to shut down what has been a perfectly safe airspace for decades because of one accident.

UPDATE: A few sources have suggested that the CAPS parachute system fired after the crash, due to the fire, and not while the plane was still airborn.

In that case, the cause of the crash seems to have been an engine failure of some kind, which resulted in a stall during an emergency turn, possibly even with an unrecoverable spin in the turn.

It's interesting to note that Cirrus planes generally don't appreciate low speed spins-- as the approved method of recovering from one is to deploy the CAPS chute.

So, my final take on the crash is that an engine mechanical in a very bad place to have one, resulted in perhaps ten seconds of flight time in which to react to it. They tried, apparently, to come about and ditch the aircraft somewhere, and possibly got into a low speed stall or a spin in which control of the aircraft was lost.

Here's an update of the assumed flight path up the east corridor, including two possible turn paths. If the plane had engine trouble during this turn, or was distracted by instrumentation or something else, it's quite possible they stalled and entered a spin which caused the aircraft to fall quickly with little or no control of the turn.

posted by Mr. Lion @ 1:26 hours | comments (0)

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