Sender: "Marvin Kaye" <marv@lancaironline.net>
To: lml@lancaironline.net
Date: Sat, 08 Jan 2005 03:39:27 -0500
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From: "Hamid A. Wasti" <hwasti@starband.net>
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Subject: Re: [LML] Approved Weights for Lancair IVP/IVPTs?
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Jeff,

If you would please bear with me for a little story, which I will follow 
with the answer to your question.

These two guys went moose hunting in Alaska.  They chartered a single 
engine airplane that dropped them off in a remote area.  They arranged 
to meet the pilot at the same location a week later.

A week later, when the pilot lands he finds the hunters with a huge 
moose that they want to bring back with them.  The pilot is very 
concerned that the airplane may not be able to carry that much weight. 
 The hunters are very insistent; last year they came to same spot in the 
same make make and model airplane, hunted an even bigger moose and the 
pilot did not have any problems loading it in the airplane for the 
flight back.

With this existence proof, the pilot decided to load the moose and take 
off.  But the plane was just too weighed down and despite his best 
efforts it was unable to clear the surrounding mountains and crash 
landed about 50 feel short of the peak.  Due to the pilot's great skill, 
the the plane came to a rest with no injuries.  The two hunters exited 
the airplane, surveyed the area and then one said to the other:  "Isn't 
that where we crashed last year?  Looks like we made it about 200 feet 
higher up the mountain this year"

The moral of the story is that just because someone has managed to 
convince a DAR to sign off on a higher gross weight, it does not mean it 
is a safe thing to do or a good idea.  Do you know if the fuselage, the 
wings and the landing gear can take that much extra weight?  What is the 
safe operating CG range at this increased weight?  What are the stall 
characteristics at the increased weight?  What is the takeoff 
performance?  What are the flutter margins at this increased loading? 
 What are the various V speeds at this increased weight?  Do you have 
engineering data to answer these questions?

Your DAR is doing the right thing in questioning how you came up with 
the weight and the CG range you came up with.  If you go with the 
factory weight, you can look to them to provide you the engineering data 
to justify the numbers they have published.  If you go with something 
higher, you really need to justify why those numbers are safe -- 
N-numbers are no substitute for engineering data.  If you can get 
engineering data from the people with higher gross weight, you should be 
able to use that and will not have to develop your own.  But if they can 
not provide you with engineering data because their DAR did not ask for 
it, then all you are saying to your DAR:  There are these other DARs 
that did not ask for data, so you should not either.  Maybe you should 
be asking the people with higher gross weights the name of their DARs, 
not the N-numbers of their airplanes.

Fly safe.

Hamid


Jeffrey Liegner, MD wrote:

> Please everyone post their approved weights for their IVPs.  My DAR 
> may bulk at anything over factory 3550 lbs unless I can show N numbers 
> with higher weights.  I'm looking for 3800 lbs, but believe some have 
> 4000 lbs approved.
>
> Jeff L
> 99% done.  DAR on 1/22/05
>