Heading System Calibration / Compensation - Piper Malibu Meridian PA-46-500TP Airplane Maintenance Manual

7
8
9
10 Upon achieving an index error of less than one
11 This completes indexing of the flux values.
(b) Heading System Calibration / Compensation
The heading system calibration / compensation should be performed upon completion of
the flux detector indexing, above, and using the same aircraft configuration specified in
the flux detector indexing procedure, above.
1
2
5D21
PIPER AIRCRAFT, INC.
PA-46-500TP, MALIBU MERIDIAN
MAINTENANCE MANUAL
After recording the above heading information, calculate the index heading errors in
Chart 7. Refer to Figure 4 to calculate errors. The following logic applies to
calculating heading errors:
For N, if indication is +, then error is +.
For N, if indication is -, then error is -.
For E, if indication is less than 90 then error is -.
For E, if indication is greater then 90, then error is +.
For S, if indication is less than 180, then error is -.
For S, if indication is greater than 180, then error is +.
For W, if indication is less then -90, then error is -.
For W, if indication is greater then -90, then error is +.
Add up the errors for both pilot and copilot (Total Error) side and enter the sum in
Chart 7. Divide the Total Error by 4 and enter in Chart 7. The result is the "Index
Error" of the flux valve.
If the index error is greater than 1 degree,
loosen the flux detector and adjust out the index
error by rotating the flux valve.
Repeat steps (6) through (8), above, until the
index error is less than 1 degree.
degree, ensure that the differences in raw data
errors for the flux detectors at each respective
cardinal heading are less than three degrees
between the two EFIS Systems, Pilot and
Copilot. Additionally, the raw data errors
between reciprocal cardinal headings, N to S
and E to W, should also be less than or equal to
three degrees. Repeating the indexing process
in a different direction, ex. +1 direction to -1 direction, may decrease the reciprocal
heading errors. If not, the flux detector must be replaced. It is highly desirable that
the index errors on pilot and copilot side be in the same direction. (Both positive or
both negative.)
NOTE: Upon completion of flux detector indexing procedure, apply torque stripe to
each of the flux detector mounting screws.
Place the Navigation Display (ND) in the normal or mission operational mode (normal
power-up).
With the ADAHRS test cable calibration switch in the closed (calibration) position,
slowly taxi the aircraft in two complete 360-degree turns. The direction of the turn
does not matter; however, a minimum time of 1 minute for 360 degree turn (two
minutes for the full 720 degrees) is required for the calibration process. The slow turn
rate permits the ADAHRS to generate more data point samples for constructing the
compensation curve. Make sure the turns are continued until the heading flag is
replaced by normal heading indication.
N
-
+
+
-
W
-
+
-
+
S
Index Heading Error Logic
Figure 4
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Apr 15/07
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