The Davtron indicator had to be removed due to indication incorrect pressure altitude. A continuity check of the harness found no errors in the wiring so the problem had to be elsewhere. Checking altitude encoder grey codes found that the B4 had to be high when it should have been low so there must have been a short. The only nearby high was the C1 so the short had to be here. An inspection of the connector under magnification revealed a tiny bead of solder between the pins of B4 and C1 which I pried out with a sewing needle.

The indicator now reads accurately and is ready for reinstall in the aircraft. It is essential that this unit function correctly not only because of it's importance in calculating takeoff performance but any inaccuracy will be shared by the transponder. ATC will rely on the altitude reported be the transponder for traffic seperation so the utmost care must be taken to insure that the Davtron indicator to insure that the Davtron indicator does not interfere with the function of the transponder.

The temprature probe location on the bottom of the aircraft near centerline 16" behind the baggage compartment bulkhead is not ideal but is a reasonable comprimise to the reccomended location. On top is out of the question becaude it will sense skin tempreture heated by the sun. In flight the probe should have little or no effect from the engine exhaust stream or engine heat trail from the cowl flaps. The readings should provide more accurate TAS calculations than could be obtained from the old fashion Aerotherm gague.