(e)  
Connect the hose to the ventilation duct and tighten the hose clamp: 1) Put the clamp on the ventilation duct and make sure that

 the T-bolt threads extend out and down. 2) Turn the clamp on the flange. a) Make sure the head of the T-bolt is less than 0.5 inch
 (12.7 mm) from the inner wall surface of the thrust
 reverser.
 3) Tighten the clamp nut.

 S 414-023-N00
 WARNING: OBEY THE INSTRUCTIONS IN AMM 78-31-00/201 WHEN YOU CLOSE THE
_______ THRUST REVERSERS. IF YOU DO NOT OBEY THE INSTRUCTIONS, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR.
 (2)  
Close the left thrust reverser (AMM 78-31-00/201).

 S 414-024-N00

 (3)  
Close the left core cowl panel (AMM 71-11-06/201).

 S 414-025-N00

 (4)  
Close the left fan cowl panel (AMM 71-11-04/201).

 S 444-026-N00

 (5)  
Do the activation procedure for the thrust reverser (AMM 78-31-00/201).

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
BAROMETRIC SWITCH - REMOVAL/INSTALLATION
________________________________________
 1.  General
_______
 A.  This procedure includes the tasks for the removal and installation of the barometric switch.
 B.  The barometric switch is found in the forward fairing of the nacelle strut.
 C.  You must open one of the access doors for thermal anti-ice (TAI) valve to get access to the barometric switch.
 TASK 75-23-04-004-001-N00
 2.  Barometric Switch Removal (Fig. 401)
_________________________
 A.  References
 (1)  
AMM 06-09-09/201, Nacelle and Engine-to-Wing Fairing Access Doors and Panels

 (2)  
AMM 20-11-25/201, Heat Gun, Soldering Guns, and/or Soldering Irons

 (3)  
IPC 75-23-51 Fig. 1

 (4)  
WDM 75-23-11, 75-23-21

 (5)  
SSM 75-23-01

 B.  
Access

 (1)  
Location Zone
 451 Strut No. 1 - Forward Fairing
 461 Strut No. 2 - Forward Fairing
 471 Strut No. 3 - Forward Fairing
 481 Strut No. 4 - Forward Fairing

 (2)  
Access Panel
 451AR TAI Valve Access Door - Strut 1
 461AR TAI Valve Access Door - Strut 2
 471AR TAI Valve Access Door - Strut 3
 481AR TAI Valve Access Door - Strut 4

 C.  
Procedure

 S 864-002-N00
 (1)  For the applicable engine, open these circuit breakers and attach DO-NOT-CLOSE tags:
 (a)  P6 Main Power Distribution Panel
 1) 6F14 ENG 1 EEAC
 2) 6E14 ENG 2 EEAC
 3) 6D14 ENG 3 EEAC
 4) 6C14 ENG 4 EEAC

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES /MAINTENANCE MANUAL ////////////////////////
ACCESS DOOR FOR THE TAI VALVE

(2 LOCATIONS)

Barometric Switch Installation
Figure 401

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 ALL  ú ú N01 Page 402 ú Oct 10/90
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
S 014-003-N00
 (2)  Do this task to get access to the barometric switch: "Open the Nacelle and Engine-to-Wing Fairing Access Doors and Panels" (AMM 06-09-09/201). Refer to the table that follows for the correct access door:
 ~............................................................ | Strut | Access Door | Name of the Access Door | .............................................................. | 1 | 451AR | TAI Valve Access Door | | 2 | 461AR | TAI Valve Access Door | | 3 | 471AR | TAI Valve Access Door | | 4 | 481AR | TAI Valve Access Door | 2...........….................…..............................1
　
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