TB 9-4920-457-35
NOTE
Start each of the following checks at approximately 2000 ft
indication on altimeter.
NOTE
The middle digit following the basic model number identifies the
vertical speed indicator installed in the TI. Table 5 lists
tolerances for each available model code. Select appropriate
(8) Repeat (6) and (7) above two times and average the three readings. The average
reading will be within the tolerance listed in table 5 for the applicable model code. Record
TI error.
(9) Repeat (5) through (8) above for remaining vertical speed indications listed in
(10) If all average indications recorded in (6) through (8) above are within tolerances
listed in table 5, annotate correction chart and place in holder on faceplate of TI. The
correction chart will show standard indications when TI indicates nominal values.
b. Adjustments. No further adjustments can be made.
Test instrument
Pneumatic pressure standard indications
indications
(fpm)
(fpm)
Min
Max
2
3
4
6
2
3
41
61
1
1
1
1
1
1
500
465
465
400
400
535
535
600
600
1000
925
925
800
800
1075
1075
1200
1200
1500
1350
1350
---
---
1650
1650
---
---
2000
---
1750
1700
1700
---
2250
2300
2300
3000
---
---
2700
2700
---
---
3300
3300
4000
---
---
---
3600
---
---
---
4400
50002
---
---
---
4500
---
---
---
5500
-500
-465
-465
-400
-400
-535
-535
-600
-600
-1000
-925
-925
-800
-800
-1075
-1075
-1200
-1200
-1500
-1350
-1350
---
---
-1650
-1650
---
---
-2000
---
-1750
-1700
-1700
---
-2250
-2300
-2300
-3000
---
---
-2700
-2700
---
---
-3300
-3300
-4000
---
---
---
-3600
---
---
---
-4400
-5000
---
---
---
-4500
---
---
---
-5500
Middle digit of 3 digit code following basic model number (see table 1).
1
Maintain vertical speed indication at highest indication used for 3 minutes, close VACUUM CONTROL valve fully,
2
and proceed to -500 fpm indication.
9
