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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 of this document has been approved 

by Transportation Equipment Factory ,PZL-Swidnik" S.A. 

under the authority of DOA No. EASA. 21J.114 

MANDATORY BULLETIN No. B0-37-07-192 

NAME-TYPE/MODEL: PZL W -3A/PZL W -3AS model and 

SERIES/NUMBER: 

SUBJECT: 

EFFECTIVITY: 

PZL W -3A/PZL W -3A model helicopters. 

All helicopters. 

MODIFICATION OF PRESSURE LINE IN HYDRAULIC 

SYSTEM 1 AND 2 IN THE SECTION BETWEEN HYDRAULIC 

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 

Manufacturer under delegated authority of ULC. 

Agnieszka Depa 

GILC-Authorized Interpreter 
I 

In the PZL W-3A/ PZL W-3A model helicopter SIN 37.07.05, and previously also in the 

PZL W-3A/ PZL W-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 unit panel (see Sketch 1). 

Further to the above, it is required to make modification of hydraulic 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- in the ground pressure line in System 2. 

After disconnecting the pipe endings from hydraulic blocks, protect them against displacement and 

contamination and plug the endings in hydraulic blocks. 

Disconnection of a.m. pipes from hydraulic blocks prevents from leakage of hydraulic oil from the 

helicopter system in case of a failure of any pipe installed in the ground pressure·line of hydraulic 

system 1 and 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 of their accomplishment, connect the disconnected pipes 37.59.234.00.00 and 

37.59.233.00.00 to the hydraulic blocks of the system. 

To eliminate the effects of leakage in any of the ground pressure lines in the hydraulic system r 

and 2, PZL-Swidnik S.A. shall introduce additional check 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 can be installed in serviceable helicopters on the basis of a separate bulletin. 

The disposition to disconnect pipes from the hydraulic block ground pressure line endings shall 

cease to be applicable when check valves are installed in the helicopter hydraulic system. 

2/6 B0-37-07-192 
IT 

Bulletin accomplishment: 

Under the scope of modification, 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 of pipes from the hydraulic block ending 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 by plugging them with the plugs 

2837A-6 or 1-8-22A GOST 13973-74 

- Fix the disconnected pipes by securing them to the struts of hydraulic blocks base using the tape 

ZN-83/3884-100202 and the clips A-ZN-82/3884-100201 (each pipe in 2 places). 

The pipes connection to the hydraulic blocks endings for the time of periodical 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 of W -3A Helicopter Maintenance Manual, Doc. No. AE 30.04.20.1 MM. 

m 

PARTS LIST 

Item Name Dwg I standard No.or type 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 

The bulletin shall be 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 

The bulletin accomplishment shall be recorded 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 ground pressure line have 

been disconnected from hydraulic blocks. 

Write this bulletin number as the basis for the system modification. 

4/6 B0-37-07-192 
Sketch 1. System assembly in the section between the hydraulic block and the ground hydraulic 

unit panel. 

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 5/6 
Sketch 1. Cont'd. 

System 2 

· block 

6/6 B0-37 -07-192