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### ,PZL-SWIDNIK" Al. Lotnik6w Polskich 1 21-045 Swidnik, Poland Tel. (+48 81)468 09 01, 751 20 71 Fax (+48 81) 468 09 19,751 21 73 EASA Approval/Certificate: · EASA. 21J.114 The technical content ofthis document has been approved by Transportation Equipment Factory ,PZL-Swidnik" S.A. under the authority ofDOA No. EASA. 21J.114 

# MANDATORY BULLETIN No. B0-37-07-192 NAME-TYPE/MODEL: PZLW-3A/PZL W-3AS model and SERIES/NUMBER: SUBJECT: EFFECTIVITY: PZLW-3A/PZL W-3A model helicopters. All helicopters. MODIFICATION OFPRESSURELINEIN HYDRAULIC SYSTEM 1

### AND 2 IN THE SECTIONBETWEENHYDRAULIC BLOCKS AND GROUND HYDRAULIC UNIT PANEL. Within 3 months after receiving the bulletin.

The original Bulletin in Polish language was approved on 12.01.2007. The English translation of the original was approved by the Manufacturerunder delegated authority ofULC. Agnieszka Depa 

### GILC-Authorized InterpreterI In the PZLW-3A/PZLW-3A model helicopter 

### SIN 37.07.05, and previously also in the PZLW-3A/ PZLW-3AS model helicopters, a leakage was found in the duralumin pipe 37.59.006.00.00 installed in the pressure line of hydraulic system 2, in the part between the hydraulic block and the ground hydraulic unitpanel (see Sketch 1). Furtherto the above, it is required to make modification ofhydraulic system on all serviceable PZL W-3A/ PZL W-3AS model and PZL W-3A/ PZL W-3A model helicopters by disconnecting the following pipes from the hydraulic blocks:

- 37.59.234.00.00- in the ground pressure line in System 1,

- 37.59.233.00.00- inthe ground pressure line in System 2. After disconnecting the pipe endings from hydraulic blocks, protect them against displacement and contamination and plug the endings inhydraulicblocks. Disconnection of a.m. pipes from hydraulic blocks prevents from leakage of hydraulic oil from the helicopter system in case ofa failure ofany pipe installed in the ground pressure·line ofhydraulic system 1and 2. The hydraulic system in the part between hydraulic blocks and the ground hydraulic unit panel is used only during periodical inspections for the performance of which it is required to use the hydraulic power unit. For the time oftheir accomplishment, connect the disconnected pipes 37.59.234.00.00 and 37.59.233.00.00 to the hydraulic blocks ofthe system. To eliminate the effects ofleakage in any ofthe ground pressure lines in the hydraulic system 

## r and 2, PZL-Swidnik S.A. shall introduce additionalcheck valves mounted on the endings of ground pressure lines of System 1 and 2 hydraulic blocks and the new pipes of a changed shape replacing the existing pipes 37.59.234.00.00 and 37.59.233.00.00. These valves canbe installed in serviceablehelicopters on the basis ofa separatebulletin. The disposition to disconnect pipes from the hydraulic block ground pressure line endings shall cease to be applicable when checkvalves are installed in the helicopterhydraulic system.

2/6 B0-37-07-192IT Bulletin accomplishment: Under the scope ofmodification, disconnect the pipes 37.59.233.00.00 and 37.59.234.00.00 (see Sketch 1) from the endings of hydraulic blocks. The work shall be accomplished per following instructions:

- Protect the roof structure against hydraulic liquid contamination by putting a vessel or rags and loosen the clamps securing the pipes to the hydraulic block base struts to enable smooth, free from distortions, displacement ofpipes from the hydraulic blockending axes and to plug them;

- Unsecure and untighten the pipe nuts from the endings. Make sure that the liquid leakage from hydraulic blocks is at minimum;

- Plug the endings at hydraulic blocks using nuts 2705A-6 or 8-22A GOST 13957-74 and covers 2843A-6 or 8-22A GOST 13976-74;

- Protect the disconnected pipe endings against contamination byplugging them with the plugs 2837A-6 or 1-8-22A GOST 13973-74

- Fix the disconnected pipes bysecuring them to the struts ofhydraulic blocks base using the tape ZN-83/3884-100202 and the clips A-ZN-82/3884-100201 (eachpipein 2 places). Thepipes connection to the hydraulic blocks endings for the time ofperiodical inspections which require use of the hydraulic power unit shall be accomplished in accordance with the general rules of proceeding applicable during inspections and maintenance of hydraulic system as specified in Subchapter 29.00.00 ofW-3A HelicopterMaintenance Manual, Doc. No. AE 30.04.20.1 MM. 

## m PARTS LIST Item Name Dwg I standard No.ortype Q-typer Notes helicopter 1. Tape ZN-83/3884-100202 I= 800 2. Clip A-ZN-82/3884-100201 4 3. Nut 2705A-6 or 8-22A GOST 13957-74 2 4. Cover 2843A-6 or 8-22A GOST 13976-74
- . 2 5. Plug 2837A-6 or 1-8-22A GOST 13973-74 2 IV Thebulletin shallbe accomplished by Operator on his own. The parts required for the bulletin accomplishment shall be supplied by PZL-Swidnik S.A. on Operator's request and cost.

B0-37-07-192 3/6

## v Thebulletin accomplishment shall berecorded in the Helicopter Log Book as follows: Pipes 37.59.233.00.00 and 37.59.234.00.00 in'hydraulic system 1 and 2 groundpressurelinehave beendisconnectedfrom hydraulicblocks. Write this bulletin number as thebasis for the system modification.

4/6 B0-37-07-192

### Sketch 1. 

### System assembly in the section between thehydraulicblock and the groundhydraulic unitpanel. System 1 with cover 2843A-6 37.59.003.00.00 

### and nut 2705A-6 or 37.59.003.00.01

Airborne valve B0-37-07-192 

### 5/6Sketch 1. Cont'd. System 2

· block

6/6 B0-37-07-192