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Date: Tue, 04 Sep 2007 11:25:38 -0400
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From: Hamid Wasti <hwasti@lm50.com>
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Subject: Re: [LML] Density Altitude Crash
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Michael Newman wrote:
> Seems like there is a lot of noise in this thread with people not collecting
> easily available data before their comments are posted.

I doubt many would consider a POH as "easily available data"  Even you 
in your post use a different POH and extrapolate based on your knowledge 
of Bonanzas, rather than using the actual POH for the particular airplane.


> I looked up the airport 061 Cameron CA. It has a 4000 foot runway and is at
> 1287 feet. Google maps show long overruns which slope uphill.

It has been close to 10 years since I was last there, but the picture on 
Google Maps 
http://maps.google.com/maps?ll=38.684000%2C-120.987528&spn=0.0156,0.0156 
(click the satellite button on the top right corner then zoom in using 
controls on the top left) is quite instructive, as is the data from 
AirNav (http://www.airnav.com/airport/O61)

The 4,051 length includes the displaced thresholds.  What you see as the 
"paved overrun" is actually the 1,509 foot displaced threshold of Runway 
31.  The accident happened when departing on runway 13, which has a 193 
foot displaced threshold.

There are 40 foot trees 410 feet from the end of the runway, so the 
FAA's 50 foot hypothetical obstruction is a very real tree in this case.


 > Using the
> Beech tables and charts for my plane at 110 degrees F 3600 pounds and 2000
> feet airport elevation I get a takeoff distance of 3500 feet to clear a 50
> foot obstacle.

One thing you did not include in your analysis is tail wind. Having seen 
the video again and paid close attention to how trees/bushes etc are 
moving, I do not think the official report of 5 knots is accurate.  The 
actual winds may well be in excess of 10 knots.

The second thing you did not take into account is the slope of the runway.


> In short given the conditions and load I would have no qualms about
> departing in a Bonanza from Cameron. My worst case numbers above show
> substantial margins.

I wonder how much of a safety margin the numbers provide once you take 
the slope and the tail wind into account.

Let me once again reiterate that lacking the actual POH for the 
particular airplane and the actual W&B data, this can only be a 
hypothetical discussion about flying out of a real airport.

Regards,

Hamid