Les Jones

News > Philip Greenspun on Cory Lidle Plane Crash

From blogger and amateur pilot Phil Greenspun:

My preliminary best guess (and at this point it can only be a guess) is that the two pilots on board the accident SR20 were cruising slowly up the East River. At some point, they decided that they’d reached the end of the little cut-out tongue of uncontrolled airspace over the East River. They attempted a 180-degree turn in an attempt to get southbound down the river toward uncontrolled airspace. An airplane in a sharp turn stalls at a much higher airspeed than when straight and level. Merely by putting the airplane into a steep bank and trying to hold altitude, they could have gone from flying to an aerodynamic stall (wings at too high an angle to the relative wind or, in simpler terms, air not moving fast enough over the wings) in a matter of seconds. At this point, the airplane is not easily controlled and a lot of bad things can happen. Low-speed low-level maneuvering, which typically happens when aircraft are trying to land, is the leading cause of plane crashes.

The discussion in comments is interesting, too.

From Phil I think the Cirrus parachute deployments are supposed to be somewhat effective even as low as 400′ above the ground. A water landing in the East River would have been preferable to a parachute landing, I think. The Cirrus parachute landing into water that I heard about resulted in serious injury to the pilot. Apparently you need the landing gear to strike something solid and absorb a lot of the force. Something like 85 percent of ditchings (landings in water) are survived and that includes guys who land in the open ocean. A plane will float for a few minutes after landing (unlike a helicopter, which sinks like a rock).

And this:

Philip: You may be right about overbanking and stalling, but I’d be more inclined to guess the opposite--that they tried too hard to avoid overbanking and stalling. As a result, they were too fast and turned too slowly, making the turn too wide (until perhaps the last moment, when they may have turned steeply and stalled while trying to avoid the looming buildings). If the turn had initially been too sharp instead of too wide, they’d probably have crashed into the river or island rather than into Manhattan, wouldn’t they?

And from a Web page called Flying Around Manhattan:

At the north end of Roosevelt Island, the East River dead-ends onto LGA’s air space. I always turn around well south of the Island, where the river is nice and wide. I warn the passengers of the G-forces and usually make a 60°-banked turn (it’s my sadistic streak – 45° is plenty to make the turn). Watch the wind – it’s usually from the west, so a left turn is into the wind. Rarely, winds are from the east, however, and then a right turn may make more sense to keep the radius small. Make sure you announce well and look behind you before turning. Do I need to tell you to be proficient in steep turns before venturing into the East River? This is not a place to practice them.