ALL  13 Page 401  Dec 25/8734-12-01
 TOTAL AIR TEMPERATURE PROBE - REMOVAL/INSTALLATION
__________________________________________________
 1.  Equipment and Materials
_______________________
 A.  Nylon Cord - V-T-295, Type 1, Class 2, Size 9 (Ref 20-30-04)
 Miscellaneous Materials.

 B.  Sealant - BMS 5-26, BMS 5-79, BMS 5-95 (Ref 20-30-05)
 Sealants and Sealing Materials.

 C.  Cleaner - BMS 11-7. Refer to 20-30-01, Cleaners and Polishes.
 D.  Resistance measuring bridge capable of measuring 0.010 ohms with an accuracy of | 0.001 ohm - Suitable attachments for connecting bridge to probe and airplane skin.
 2.  Referenced Procedures
_____________________
 A.  24-22-00, Maintenance Practices (Apply Power)
 3.  Remove Total Air Temperature Probe__________________________________(See figure 401.)
 A.  On airplanes with clearance notch, from inside airplane, disconnect electrical connector and flexible hose (on airplanes with aspirated probe) on probe base and place a protective cover on both halves of connector and flex hose.
 B.  Dig just under surface of sealant surrounding probe base to expose nylon cord. Grasp cord and pull out to break up sealant.
 C.  Remove six screws from probe mounting flange.
 D.  Grasp probe and pull directly out from aircraft skin until electrical connector on base of probe is exposed.
 CAUTION: EXTRA FORCE ON PROBE BASE MAY BE REQUIRED TO BREAK
_______ GASKET SEAL WHEN GASKET RELEASES, DO NOT ALLOW PROBE TO PULL AWAY FROM AIRCRAFT WITH SUCH FORCE AS TO DAMAGE CABLE AT PROBE BASE.
 E.  On airplanes with clearance notch, disconnect electrical connector and flexible hose (on airplanes with aspirated probe) on probe base and place a protective cover on both halves of connector and flex hose. Restrain connector and hose so they do not fall back inside fuselage.
 4.  Install Total Air Temperature Probe___________________________________(See figure 401.)
 A.  Locate mounting hole. Remove and discard old gasket, if any.
 B.  Remove old sealant from mounting hole. Clean and prepare surface and sides of mounting hole.
 C.  On airplanes without an aspirated system,
 cap off the aspirator tube on the probe before installation.

 NOTE: On airplanes without an aspirated system an aspirated probe can be
____ installed if the aspirator tube is capped off. A non-aspirated probe cannot be installed on an airplane with an aspirated system.
 D.  On airplanes with clearance notch, remove protective covers from electrical connectors and flexible hose (on airplanes with aspirated probe). Connect aircraft connector and flexible hose to probe base and lock down.
 E.  Slip cable and flexible hose (on airplanes with aspirated probe) inside aircraft while placing cylindrical probe base into mounting hole).
 EFFECTIVITY
 
 ALL  05 Page 401  Aug 25/9334-12-02

ON AIRPLANES WITH ASPIRATED PROBE
Total Air Temperature Probe Removal Figure 401
EFFECTIVITY
ALL 749 Page 402

34-12-02
Apr 25/81
 F.  Position probe flange and gasket so they line up with mounting holes in airplane skin. Check that probe is facing forward (wide intake at top pointing forward, exit holes along back of strut facing aft).
 G.  Verify that probe base is seated flush with mounting plate and gasket. Install six machine screws in probe base mounting holes and tighten.
 H.  Install nylon cord in bottom of cavity around probe base prior to sealing (Ref 20-30-04).
 I.  Measure resistance between total air temperature probe body and airplane skin. Observe that bonding resistance is not greater than 0.010 ohms.
 J.  Test total air temperature probe electrical connections as follows:
 (1)  
Provide electrical power (Ref 24-22-00).

 (2)  
Verify power is applied to pilots' total air temperature indicator to test probe No. 1 and to flight engineer's total air temperature indicator to test probe No. 2.

 (3)  
On pilots' or flight engineer's total air temperature indicator, note that OFF flag is not displayed and indicator is reading approximately airfield temperature.

 (4)  
Remove electrical power if no longer required (Ref 24-22-00).

 K.  Test the total air temperature probe bleed air system as follows:
 (1)  
Air must be applied to the applicable total air temperature (TAT) probe by one ofthe following methods:

 (a)  
　
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