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Old 22nd October 2009, 07:00 PM   #3836
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Join Date: Jul 2007
Location: In Space
Posts: 3,693
Originally Posted by jaydeehess View Post
However, his own statement above indicates that he considers the PA to be more accurate than the Radalt, once it is adjusted for local pressure.
Nobody, but nobody uses a barometric altimeter in lieu of a radar altimeter below 500' AGL. This includes any military or the airlines.

For landings in large aircraft such as a C-5 or a B - 747 where judgment of height is difficult and critical, all altitude references for landing are taken directly from the Radar Altimeter exclusively. Pressure variances between the location where the local pressure correction to PA is computed and the location of the aircraft can and will produce differences. Even when both locations are the same, Radar Alt is still used for determining height. Never once in my flying career have I ever relied on a barometric altimeter close to mother earth. It is a quick and easy way to end your career prematurely.

Cap'n King Air's comments regarding a 13' error in AA 77's Altimeter is a humorous distraction with minutiae. Can someone please tell me how all of those "verified by the FAA" cult members he refers to know if their altimeter is not lagging. How do they know just how accurate their altimeter is during all phases of flight. All they really know is how accurate it is on the ground. They can compare the two altimeters, but they don't know whether both are erroneously are reacting in the same way to the same phenomena.

AA 77 was traveling well above design parameters, so, as R Mackey said, who knows what was happening at the static ports.

I'm not at all surprised that "beachnut's dolt" won't give up the delusions. He has too much invested and will continue to BS his way through any data that is obviously determined to be accurate, even to the point of lying, cheating, and stealing to continue just as he's doing with this baro altimeter versus radar altimeter accuracy BS.

ETA: a correction here. We used to shoot Ground Controlled (GCA) approaches to 200' agl 1/4 mile visibility without a radar altimeter. What I said above applies to aircraft with a Radar altimeter. On Precision approaches the Decision Height is based on a barometric altimeter, but you can rest assurred that the pilot has one eyeball on the radar altimeter (if one is available).

Last edited by Reheat; 22nd October 2009 at 08:44 PM.
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