Thunderbirds and Altimeters

I've been back channeling for two days now with friends who are
ex-Thunderbirds and professional pilots in other professions. Most of us are
puzzled by the report although not at all puzzled by the results of
Stricklin's mistake!
There's something about this report some of us don't quite get, and it
concerns the zero set on the altimeters. The TB fly a zero set altimeter for
a show. It's not only basic for low altitude acro work, but it's specified
in the regulations for the Thunderbird mission and procedures. (the old
regulation anyway. haven't seen the revised one yet)
My guys however, were on the T38 team, and the TB regulation for practice
might have been changed since then. However, none of us believe that
Stricklin took off with the altimeter set for the elevation at Mountain
Home, which is 2996 feet ASL. That leaves only one scenario; that the
present Viper team must be using a MSL base at Nellis for practice because
of the mountains at Indian Springs. If this is true, then we still can't
figure out why Stricklin would reverse on the roof of his maneuver with a
target altitude of 1600 feet which is basically what happened. It just
doesn't make sense to us. If the team is using a MSL base at Nellis, and
Stricklin was using that base in his mind when he reversed; the elevation at
Nellis is 2000 feet. That would have put his reverse at 4500 feet for the
Viper instead of the 1600 plus he used. 1600 is way low for the Viper even
for a zero set altimeter reference It's very puzzling!!!
Also, there's been a lot of talk about not being able to zero altimeters at
some high elevation airports. This is puzzling also. The Kollsman range,
which is also the basic baro range in the Viper's CADC which drives the
Viper's altimeter in both ELECT and PNEU backup, is aprox 22.00 inches on
the low side and 32.00 inches on the high side. (I had to check this out
with some buddies of mine, as I'd forgotten the range in the Kollsman
myself!! :-)
This gives you, even figuring the 1 inch per thousand rule, an elevation
reset capability to a zero reset before takeoff of 10, 000 feet. This
basically allows a zero reset anywhere in the U.S. at least, allowing for a
standard atmosphere. I don't think I'm missing anything here, but I might
have.....getting older you know!! :-) I just can't remember a zero set being
any problem for me during my tenure as a demonstration pilot.
The Thunderbird's are locked up tighter than a drum right now, and answers
from the present team are not easy to get; so the bottom line so far for us
old timers trying to figure this out is that the team indeed does use a MSL
reference at Nellis because of the mountains, but resets to a zero altimeter
set before takeoff at the show site. If this is the case, it's
understandable to me how Chris Stricklin could have made the mistake he did.
I'll tell you up front. I can sympathize with Chris Stricklin, or anyone
else for that matter who has to work low altitude acro this way. If there's
one thing that will kill you doing low work it's non-standardization. If the
Birds have to use a MSL calculation for their roof target altitudes at
Nellis for a vertical plane maneuver because of the mountains, then revert
to a zero set when doing a show; that in my opinion is bad news! It's only a
matter of time when things like this catch up to you when doing low work in
high performance airplanes.
Chris Stricklin is a damn good pilot. He's also a damn lucky pilot!
What happened to Stricklin has happened to a lot of very good pilots who do
low work. If all this reporting is true, he was simply bitten by non
standardization! I understand the situation's being looked at closely by the
Air Force. That's one good thing anyway, although I don't see how they're
going to change anything unless they can take the mountains at Nellis out of
the Thunderbird equation.
Frankly, the whole damn thing is puzzling to us; us being myself and a few
ex-Thunderbirds. I know I'll probably pick up the straight scoop sooner or
later through my grapevine, but for right now, this report, and putting it
together for a clear picture of what happened to Stricklin is one large
puzzle in progress.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
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