Comments on: Cirrus SR20 crash in Manhattan

By: Anonymous

Anonymous — Wed, 28 Mar 2007 21:33:42 +0000

This is all educated speculation. They weren’t flying below the building tops. It is almost certain the airplane became stalled while making the turn at an altitude above the buildings. While the physics of the turn show that it can be done with, what, a 45 degree bank, nobody does that kind of math prior to a flight. Pilots turn in a way that feels natural. Most likely they started with a 20-30 degree bank turn. Things looked to be going well at first, then it became apparent they would have to steepen the bank. To compensate for not being at 45 degrees the whole time, the second half of the turn would have had to be much steeper. Given that this is speculation and I’m not going to do the math, let’s say it needed to be 60-65 degrees of bank to finish the turn (most likely with full rudder and opposite aileron to stop the overbanking tendency). At that bank angle, stall speed for the Cirrus drastically increases (and despite all the comforting self-press from Cirrus about their stall characteristics, these airplanes are actually very finicky in a stall, especially with wings not level). They most certainly entered a stall/spin and descended in uncontrolled or semi-controlled flight. This would have been from an altitude too low for the parachute to be of any benefit. At that low of an altitude, traditional stall recovery of pitching down and adding power would have flown them right into a building anyway. This is by no means the first accident of its kind, even in a Cirrus. It is only high-profile because it involved an athletic star and a building in New York City. This accident has happened many times on a base to final turn, with non-famous pilots, in middle America, hitting trees or fields instead of apartment buildings.

On a side note, I don’t understand how that corridor can legally satisfy the requirements of an aircraft being 1000′ above and 2000′ horizontally from any structure. The corridor is less than 4000′ wide, so you are inherently within 2000′ horizontally from buildings on one side or the other.

By: Neal S.

Neal S. — Mon, 20 Nov 2006 19:47:08 +0000

Regarding turning in a small radius:
In the case of Lidle, it should have been obvious that a turn is made into the wind if the terrain is reasonably flat as in the NY corridor. Pilot inexperience and error.
I fly in Colorado.
In the case of flying up a mountain valley, which usually narrows as you approach the vertex, and you are obviously not going to make it (airplanes climb at 7 degrees, mountains rise at 35 degrees or more; the general angle of repose) you are left with little choice if you wait too long; there is not enough space to execute level turn. There is, however, a manouver that can save the day: use a hammer head turn. If practiced out on the flat it is an easy solution to that problem. The features are that, even in best angle of climb speed you can trade that speed for enough altitude to execute a hammerhead and come back down nearly on your same track and recover above the altitude you started at. The execution is: assuming that you are already at full power, best angle of climb and realize that you won’t clear the pass, pull the airplane up in as fast a “launch” climb as you can, trading speed for altitude, then just a you begin to lose alieron control, kick left rudder all the way (single engine plane), the airplane will turn about the yaw axis and head down in a nearly vertical attitude. You keep the yoke back as far as possible as soon as the nose is pointed down and you will recover straight and level a little higher than your entry altitude and heading 180 degrees from your entry course. Yes it takes practice but it can be learned and used with confidence. Go out to a practice area, find a road, get about 4000′ AGL and try it. Start slow, approach at a near-stall, power off, pull the nose up as hard as you can, kick the rudder, spin about and pull back the yoke. Progress to faster speed and more power until you feel confident to do it at full power and best angle of climb (the position you are most liable to find your self in when realizing that a) you won’t make the pass and b) there isn’t enough room to level turn).

By: Anonymous

Anonymous — Tue, 07 Nov 2006 02:52:15 +0000

The thoughts of an old CFI.

I can’t imagine a CFI of any experience allowing his student to attempt a 180 down wind turn at below the roof top levels, in the confines of the East River. Only a very bold pilot (or a very stupid one) would intentionally attempt such a maneuver. One only needs to remember his S turns across the highway or turns about a point as a student to realize the effect of wind in a down wind turn.

With that in mind, I give Lidle’s CFI–Tyler Stranger, the benifit of expert judgement. I do not believe that he would even think of making such a turn at that altitude, while being aware of his proximity to the buildings.

I strongly feel that an event of catastrophic preportion occurred. A sea gull through the windshiel, for example. The airplane would be instantly out of control.

I have never flown the corridor. But I have crossed the river by ferry in days gone by and seen the gulls that trial the pleasure boats, searching for the bits of garbage that might be tossed overboard. I am sure that they still frequent the river, because that is what sea gulls do. And they fly high, too. I have dodged them at several thousand feet over the New England coastal areas, often far inland from the sea.

The NTSB and the FAA made no mention of finding any evidence of a bird strike. Obviously, evidence such as feathers and flesh would have been destroyed in the resulting fire.

Ken B.

By: Peter T.

Peter T. — Fri, 03 Nov 2006 21:27:30 +0000

Below is a link to an Associated Press article (via ESPN.COM) with news that the NTSB cites pilot error and wind as the probable cause of Lidle’s fatal plane crash. It’s a preliminary ruling; the final ruling will be at a later date.

The report states that Lidle’s plane attempted a U-turn with only 1,300 feet of room for the turn, which would have required the aircraft to bank so steeply that it might have stalled according to the NTSB.

http://sports.espn.go.com/mlb/news/story?id=2648466

By: Mark C

Mark C — Fri, 20 Oct 2006 19:41:12 +0000

I don’t think it matters much if the military can intercept a small general-aviation craft — they simply aren’t capable of doing much damage, and the possible collateral damage from trying to shoot them down may be worse. Would you rather have a Cessna crash into your office building or a Sidewinder missile?

Even loaded up with explosives, a small plane has a miniscule cargo capacity compared to an automobile. The real urban threat is a truck loaded with conventional explosves (ala OK City or the original WTC bombing) or a dirty bomb. Small planes are irrelevant.

By: philg

philg — Fri, 20 Oct 2006 15:42:36 +0000

Jared: Watch United 93, which, I think was a fairly accurate reconstruction, to see what our military capabilities are like. Due to a combination of factors, not least the fact that all commands go through a large bureaucracy and mostly by telephone, it takes our military a long time to get ramped up. When the military is already tasked with intercepting small planes and in the area, they seem to do a fine job. I was flying the R44 into PSM back in August and heard a Piper Malibu calling air traffic controllers to ask about the F16 that was shooting flares at him. Tellingly, the controller had no idea who or where the Malibu was and had to go through the standard process of “type in the following transponder code and then squawk ident” then had to go offline to make a phone call or two and figure out how to coordinate with the Air Force. But that was a case where they knew in advance that they were going to have to do a few interceptions over a few days and just kept F16s circling constantly (we strengthen America against our oil-rich enemies by buying more Jet-A fuel from those enemies… )

Jacqueline: You see plenty of Piper Cub-style planes in the Northeast! All of the banner towers are in slow old planes like this. The main difference is that up here we don’t carry a big file in our aircraft to smooth out dings in the prop after landing on a gravel strip.

By: Jacqueline A. Lott

Jacqueline A. Lott — Wed, 18 Oct 2006 17:16:01 +0000

“People can’t shake the idea that a plane with a parachute is safer than a plane without one, though in this situation, the safest plane would have been an old slow cheap one that could be flown slowly and therefore turned tightly.”

Well stated. As someone with only a little flight training, but most of my flight time in taildraggers in Alaska, this sentence really jumped out at me. I can’t fathom flying in NYC’s airspace… I’m used to flying in and out of airports where there’s not even a tower and landing on gravel strips where the main concern is whether or not there’ll be wildlife in the way. If I could have any plane of my choice, I’d probably ask for a shiny new Husky, but I’d be absolutely delighted with a trusty old Super Cub. Bet you don’t see too many of those flying around New York, though (I visit frequently, was just there last month… next time I’ll keep an eye on the skies a bit more to see what people are flying).

By: Jared

Jared — Wed, 18 Oct 2006 07:38:24 +0000

This was briefly mentioned, but again quickly seemed to go out of the minds eye.

What would really happen if a private general aviation plane had to be intercepted by a military class jet? Assuming even with a Mach 1.8 top speed that it actually got to the area before the plane was to be intentionally or unintentionally crashed.

Can a military Jet easily identify a plane such as this? At what range? What does a sidewinder do to a small plane such as this, and can it even engage it?

The closest situation I can think of was Pain Stewarts Jet that was flying on autopilot and gave the intercepting jets enough time to engage it if necessary. But given this and that kid landing at Red Square, are these planes too small and numerous to effectively track?

Anyone have any ideas?

By: philg

philg — Mon, 16 Oct 2006 14:53:52 +0000

Robin: They were flying an older Cirrus, which probably wouldn’t have had a terrain warning system (the new ones usually do, though our 2005 does not because we are cheapskates). In any case, they would probably have had to disable any terrain warning system during a flight that low near a city because it would have been squawking constantly. We have a handheld Garmin 296 in our Robinson R44 helicopter and, even on the lowest sensitivity setting, it gets unhappy when we fly around the skyscrapers of downtown Boston. We don’t have a cable running from it to our audio panel, so we only get on-screen text and graphical warnings.

The terrain warning system is most useful for (1) flying low in a helicopter where you might miss a radio tower, and (2) flying in the clouds in an airplane where the terrain warning system provides a backup in case you get grossly confused about your position on an instrument approach and are heading toward a mountain. When you are intentionally maneuvering close to obstacles, I don’t think the system is useful.

Suzanne (sis): Flight instruction is actually safer, statistically, than flying cheap little airplanes for transportation. If the weather is miserable and you’re stuck in a motel in Winslow, Arizona trying to get to California, you are tempted to take off. If the weather is miserable and you’re preparing to leave your house in Cambridge and drive out to Bedford to teach a guy how to fly around in circles over Hanscom Air Force Base, you call the guy to reschedule.

By: Robin

Robin — Mon, 16 Oct 2006 04:53:41 +0000

doesn’t the Cirrus SR20 have an onboard audio alert system – would they not have heard a verbal warning telling them they are about to hit terrain or would that warning have come too late to get out of the jam; or could it have caused them to panic ultimately hastening their demise?