REFLECTOR: OT Plane hits an apartment building in NYC

Chuck Jensen cjensen at dts9000.com
Sat Oct 14 13:35:22 CDT 2006


Emanuel, as you were alluding to, even if they were doing twice a
standard rate turn, it would still take them 30 seconds to reverse
course.  A 20kt crosswind has a velocity of 34 fps.  In 30 seconds, the
wind will have pushed the plane half way across the river, so now they
must reverse course in 1/2 the width of the river.  And of course, if
they didn't 'hug' the right side of the river before starting the turn,
they would have <2000' to work with.  In addition, they were probably
half way through the turn before it became apparent that they were in
trouble and tried to crank it in tighter; potentially resulting in an
accelerated stall, explaining the 'aerobatics' that were observed.

In highly technical statistical terms, the odds of successfully making
that course reversal for the average pilot, could be characterized as
'fat chance.'  About the same chance as John Jr. making the over water
flight at night in poor visibility.  It can be done, but the odds are
tilted the wrong way.

Chuck Jensen
Do Not Archive
 


> -----Original Message-----
> From: reflector-bounces at tvbf.org 
> [mailto:reflector-bounces at tvbf.org] On Behalf Of Emanuel Lewis
> Sent: Saturday, October 14, 2006 1:34 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: OT Plane hits an apartment building in NYC
> 
> 
> The turning radius is not a function of the aircraft, per se, it is a 
> function of the aircraft's TAS and bank angle.  For those 
> mathematically 
> inclined:
> r(ft)~v squared (kts) / 11.26 tan (phi), where phi is the 
> bank angle. At a 45 degree bank angle 100 kts will give you a 
> radius of about 900', at 
> 150 kts the radius goes up to about 2000'.
> The width of the East River is about 1600', so we are talking 
> about an 800' 
> radius.  To have an 800' turning radius at 100 kts you need a 
> bank angle of 
> about 52 degrees, at 150 kts the bank angle would have to be about 67 
> degrees.  There was a 15 - 25 kt wind out of the east to add 
> to the problem. I have flown the corridor in my Velocity.  
> You fly to the right of the 
> centerline of the river (either Hudson or East) and make your 
> turns to the 
> left to reverse course.
> Need I say more.
> Manny Lewis
> CFI/II
> 
> ----- Original Message ----- 
> From: "John Dibble" <aminetech at bluefrog.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Friday, October 13, 2006 10:40 AM
> Subject: Re: REFLECTOR: OT Plane hits an apartment building in NYC
> 
> 
> > This is starting to make some sense, but the instructor should have 
> > been
> > able to make the required steep U-turn.  Wonder if they 
> forgot about the 
> > reg that says you
> > can violate any regulation (ie B airspace) if deemed 
> necessary for safety.
> > Is there any data on the turning diameter for a Velocity as 
> a function of 
> > bank angle/speed?
> >
> > John
> >
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