Ask The Pilot on the NYC crash

wow that article should be posted up on every street corner in NYC, and mailed to everyone that isn't a pilot
and i totally agree when he says that putting a no fly zone over the city wont do anything to stop terrorists...are people really THAT stupid??? People think that since there is a no fly zone, that there is a giant fence in mid air that planes cant fly through..
good find

Ant
 
What a great article, and I'm printing it out for folks in my office.

Particularly true, the statement that "There's limited tolerance for rational debate in America these days"
 
It says:
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to read this article and all of Salon for free "​

Where's the Sponsor logo?

:dunno:​
 
Keith Lane said:
Where's the Sponsor logo?
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That is the sponsor logo (The Prestige). Click on it, and an ad will be displayed for about five seconds. Then click on "Enter Salon" in the lower right corner of the screen.
 
Here's another article on this subject by a NYC Cirrus pilot:

http://blogs.law.harvard.edu/philg/2006/10/11/cirrus-sr20-crash-in-manhattan/

Lots of comments by readers.

My favorite comment from the article:

I was interviewed by a New York City radio station this morning. The interviewer, as have most journalists, seemed very interested in the Cirrus’s parachute. 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. The Cirrus is a great plane for going straight and level on a 400-mile trip, but its virtues become liabilities when trying to fly low and slow.
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Troy Whistman said:
Here's another article on this subject by a NYC Cirrus pilot:

http://blogs.law.harvard.edu/philg/2006/10/11/cirrus-sr20-crash-in-manhattan/

Lots of comments by readers.

My favorite comment from the article:
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That's an interesting comment. It was my understanding that the Cirrus has excellent low speed handling qualities. Since the tightest turn is actually made at Va, I'm not sure its low speed handling is really the issue, but I'm curious how its flaps up stall speed compares to that of a 172 (for example).

Chris
 
From the article:
"The Upper East Side is not Disney World," howled Rep. Carolyn B. Maloney, a Democrat representing Manhattan's East Side, speaking in a New York Times article. "The F.A.A. has a pre-9/11 mindset."
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Yup. It's the home of the rich and famous. Still keeping the average riftraft out. But surely, if we don't have a pre 9/11 mindset (which is exactly what--SAFETY FIRST), then the terrorists have won. Like locks on a door, a NO FLY zone will only keep honest people honest and infringe on their rights. A determined thief will still get in.
 
cwyckham said:
That's an interesting comment. It was my understanding that the Cirrus has excellent low speed handling qualities. Since the tightest turn is actually made at Va, I'm not sure its low speed handling is really the issue, but I'm curious how its flaps up stall speed compares to that of a 172 (for example).

Chris
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How 'bout if you reduce power, slow to the white arc, and put in a notch or two of flaps when you're doing a sightseeing tour? I've done that.
 
mikea said:
How 'bout if you reduce power, slow to the white arc, and put in a notch or two of flaps when you're doing a sightseeing tour? I've done that.
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Seems like a great idea to me. Why would you be in a hurry to scream past the scenery? Slow down a bit and enjoy the scenery. Of course, it's probably only important from a safety perspective if you think you might need to make a tight turn during a sightseeing tour, such as on the East River or heading up a valley in the mountains.

Chris
 
im wondering how you figured the tightest turn was at manuevering speed? in my flight performance class last year we calculated a cornering speed which essentially was just above the stall speed for the max angle of bank you could hold altitude at.
 
tonycondon said:
im wondering how you figured the tightest turn was at manuevering speed? in my flight performance class last year we calculated a cornering speed which essentially was just above the stall speed for the max angle of bank you could hold altitude at.
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What you're saying is essentially correct. The turn radius varies with the square of the velocity and one over the tangent of the angle of bank (it is independent of aircraft mass, by the way, which is interesting). So you want to maximize your bank and minimize your speed. Of course, as you imply above, the stall speed increases with angle of bank if you assume a level turn (there's no reason you can't lose altitude if you have some to spare, which would allow you to tighten the turn even further. The analysis is usually done assuming a level turn, as you often don't have altitude to spare in a canyon turn situation).

What you forgot to mention above is that you need the stall speed for the max angle of bank you can hold altitude at without exceeding the g limit of the aircraft. You can bank an aircraft at 89.99 degrees in a level turn just fine as long as you don't mind pulling hundreds of g's. Of course, we don't want to rip the wings off (or lose consciousness), so we turn at the angle of bank which results in the positive g limit of the aircraft. We also want to go as slowly as we can, so we fly at (or just above) the stall speed for that g force. What's the speed that results in a stall right at maximum g? -- Maneuvering Speed.

In fact, I believe that's why it's called maneuvering speed. It's the speed at which you're most maneuverable. I think it comes from dog fighting parlance, not aircraft certification parlance.

There's a really good explanation, including a graph, here.

Chris
 
All this stuff about Va is the theoretical best, of course. I'm a low time pilot, and I'm pretty sure that I shouldn't be turning close to stall speed in a wicked high bank. I've been told that when things start to get sketchy to slow things down, drop a notch of flaps, and to turn if required at 45-60 degrees of bank. The performance of the turn isn't degraded that far, and I'm more likely to survive the maneuver.

Chris
 
cwyckham said:
What you forgot to mention above is that you need the stall speed for the max angle of bank you can hold altitude at without exceeding the g limit of the aircraft. You can bank an aircraft at 89.99 degrees in a level turn just fine as long as you don't mind pulling hundreds of g's. Of course, we don't want to rip the wings off (or lose consciousness), so we turn at the angle of bank which results in the positive g limit of the aircraft. We also want to go as slowly as we can, so we fly at (or just above) the stall speed for that g force. What's the speed that results in a stall right at maximum g? -- Maneuvering Speed.
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In theory, that's great... But in reality you might want to go a little faster and have a hair less bank. You want maximum G, yes, but you do NOT want to stall. :no:
 
silver-eagle said:
From the article:
Yup. It's the home of the rich and famous. Still keeping the average riftraft out. But surely, if we don't have a pre 9/11 mindset (which is exactly what--SAFETY FIRST), then the terrorists have won. Like locks on a door, a NO FLY zone will only keep honest people honest and infringe on their rights. A determined thief will still get in.
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I live here too. And I'm not rich or famous!

I agree with the rest of the post, although I'm not sure how great it is to compare the ADIZ like a lock on the door. To me, it's a whole lot more like only having a super secure lock on the locker where the family leaves the garden hose and nothing on the front door.

And Chris, its nice to have you on these boards
 
yea chris after i posted i thought about it more and realized that what you were saying is pretty much correct. ill have to reread some of my performance book but it seems to me that you could get as good or better turn radius using a much slower speed and shallower bank angle without getting anywhere near ripping the wings off G loading
 
tonycondon said:
yea chris after i posted i thought about it more and realized that what you were saying is pretty much correct. ill have to reread some of my performance book but it seems to me that you could get as good or better turn radius using a much slower speed and shallower bank angle without getting anywhere near ripping the wings off G loading
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I believe that there is no way of getting a better turn radius than at Va and maximum g, but you do reach a point of diminishing returns. The same article I quoted before talks about using a 45 degree bank with one notch of flaps. If you look at the graphs, the radius is very similar to the Va turn with no flaps (flaps are usually limited to 2g, so you can't use them in the Va max g turn). It would also be a much safer maneuver for low time pilots such as myself.

All of the above also assumes a coordinated, level turn. If you lose altitude, you can get the same bank angle for less g, allowing you to bank further than the 75 degrees of bank that results in the 3.8g structural limit. Again, you wouldn't catch me banking further than about 60 degrees until I get my aerobatics rating, this is just a theoretical point for somebody such as myself.

I'd be very interested in what your performance book has to say about the issue.

Chris
 
well
i started to write out a ton of complicated equations about calculating maximum load factor in level turns and stalling and on and on. then saw this itty bitty paragraph that said:

Aircraft Performance and Design by John D. Anderson Jr. said:
"Finally, we note that the structural design limits of a given airplane represent a practical, mechanical constraint on the load factor. This constraint will be discussed in Section 6.5.
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so essentially here it is.

LoadFactor = Lift/Weight = 1/2*rho*Velocity^2*CoefficientofLift*WingArea/Weight

Maximum Load factor equals all that stuff with Maximum CoefficientofLift inserted (ie airplane is on edge of stall)

Solve the above equation for Velocity and you get:

Velocity = ((2*LoadFactorMax*Weight)/(rho*CoefficientofLiftMax*WingArea))^1/2

Use the Max Load factor based on structural limits and max Coefficient of Lift based on wing design and that will be you "corner velocity" or as pilots call it "Manuevering speed"

The only time this would not be true is if 1) you are assuming level flight and 2) for some reason the maximum attainable load factor to maintain level flight was lower than the maximum structural load factor. I have a feeling as this is very rare as the book says

Aircraft Performance and Design by John D. Anderson Jr. said:
"...this point simultaneously corresponds to the smallest possible instantaneous turn radius and the largest possible instantaneous turn rate for the airplane."
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Thanks for making me think about this guys, has been a very interesting excercise and its actually fun to make myself go back through and REALLY learn this stuff!
 
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