ASB No. AS355-26.00.10 

Revision 0 2015-07-02 Page 1/23 

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 Civil version: NP 

 

ALERT SERVICE BULLETIN 

SUBJECT: FIRE PROTECTION - Engine fire extinguishing system 

 Crossed connection in the distribution system of the engine fire extinguishers 

 Corresponds to modification 073990 

Revision No. Date of issue 

Revision 0 2015-07-02 

Summary: 

The purpose of this ALERT SERVICE BULLETIN is to: 

- restore configuration of the position of the squibs on each of the fire extinguishers in line with the control buttons. 

- supersede ALERT SERVICE BULLETIN 26.00.09. 

Compliance: 

Compliance with this ALERT SERVICE BULLETIN is mandatory. 

For the attention of 
 ASB No. AS355-26.00.10 

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1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/Installed equipment 

Helicopters POST MOD OP-3931 (Installation of Arrius 1A1 engine fire extinguishing system) but 

PRE MOD 073990. 

NOTE 

Refer to the Individual Inspection Record (or RIC AMS) and 

aircraft log book to identify the actual modification status of 

the aircraft.

1.A.2. Non-installed equipment 

- RH medium equipped pipe P/N 355A59-0608-00 

- RH short equipped pipe P/N 355A59-0607-00 

- LH medium equipped pipe P/N 355A59-0602-00 

- RH nozzle pipe P/N 355A59-0604-00 

- LH nozzle pipe P/N 355A59-0603-00 

- LH nozzle pipe P/N (variant: hoist capable) 355A59-0617-00 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON 

During an inspection of the engine fire extinguishing system, the technician found that the LH discharge 

system of the fire extinguishers was connected to the RH engine compartment and the RH discharge system 

was connected to the LH engine compartment. 

Consequently, in case of fire in one of the engine compartments, the pilot, by pressing the fire extinguishing 

buttons corresponding to the engine compartment on fire, activates the discharge of the fire extinguishers in 

the other engine compartment. 

Pending a modification to the fire extinguishing substance distribution system, Airbus Helicopters had 

requested, through ALERT SERVICE BULLETIN 26.00.09, the crossed connection of the position of the 

squibs on each of the fire extinguishers so that the firing control buttons correspond to the relevant engine 

compartments. 

This modification (073990) being defined, Airbus Helicopters requests, through this ALERT SERVICE 

BULLETIN to restore configuration of the position of the squibs on each of the fire extinguishers in line with 

the control buttons and modify the discharge system. 

This ALERT SERVICE BULLETIN supersedes ALERT SERVICE BULLETIN 26.00.09. 
 ASB No. AS355-26.00.10 

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1.D. DESCRIPTION 

This ALERT SERVICE BULLETIN consists of: 

- Restoring configuration of the squibs to match the new positioning of the fire extinguisher discharge heads. 

- Removing the label located on the instrument panel or the yellow adhesive located on the pipes, added 

during compliance with ALERT SERVICE BULLETIN 26.00.09. 

- Installing new discharge system pipes. 

1.E. COMPLIANCE 

1.E.1. Compliance at the works 

Helicopters/installed equipment: 

Not applicable. 

 Non-installed equipment: 

Not applicable. 

1.E.2. Compliance in service 

The works must be performed on the helicopter by the operator. 

Helicopters/installed equipment: 

Comply with paragraph 3. of this ALERT SERVICE BULLETIN, no later than within 12 months as from 

receipt of this ALERT SERVICE BULLETIN, issued on the date mentioned in page footer. 

 Non-installed equipment: 

The components mentioned in § 1.A.2. must be scrapped without exceeding 12 months. 

Building up spares stocks related to compliance with this ALERT SERVICE BULLETIN is left to the 

operator's initiative. 

1.F. APPROVAL 

 Approval of modifications: 

The information or instructions relate to modification 073990 which was approved on May 8, 2014 by the 

EASA for helicopters of civil versions subject to an Airworthiness Certificate. 

 Approval of this document: 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved 

on July 1, 2015 under the authority of EASA Design Organization Approval No. 21J.056 for helicopters of 

civil versions subject to an Airworthiness Certificate. 
 ASB No. AS355-26.00.10 

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1.G. MANPOWER 

For compliance with this ALERT SERVICE BULLETIN, Airbus Helicopters recommends the following 

personnel qualifications: 

Qualification: 

2 Mechanical Technicians, 

1 Avionics Technician, 

1 Pilot. 

 Time for the operations is indicated for reference, for a standard configuration. 

Time for the operations: 

22 hours approximately for Mechanical Technicians, 

1 hour approximately for the Avionics Technician, 

1 hour approximately for the Pilot. 

The estimated helicopter downtime is approximately 3 days. 

1.H. WEIGHT AND BALANCE 

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS 

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD 

Not applicable. 
 ASB No. AS355-26.00.10 

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1.K. REFERENCES 

The documents required for compliance with this ALERT SERVICE BULLETIN are as follows: 

MCS: 26.20.00: Engine fire extinguishing 

MET: 12.00.00.308: Hydraulic reservoir draining and filling 

MET: 21.20.00.401: Heating or demisting valve - Removal - Installation 

MET: 24.00.00.301: Electrical generation: General instructions 

MET: 25.63.00.401: Removable components : Removal - Installation 

MET: 26.20.00.401: EXTINGUISHING: Squibs - Removal - Installation 

MET: 26.20.00.402: Cowling fire extinguishing cylinders (double head): Removal - Installation 

MET: 26.20.00.403: Safety covers of push-buttons: Removal - Installation 

MET: 26.20.00.404: Supports and pipes (MOD OP3931): Removal - Installation 

MET: 26.20.00.601: Fire extinguishing system: Check 

MET: 29.00.00.301: General instructions for hydraulic power 

MET: 53.00.00.403: MGB and engine cowlings: Removal - Installation 

MET: 60.00.00.301: General instructions - Mechanical system 

MET: 71.06.00.401: Engine: Removal - Installation 

MET: 76.20.00.401: Removal - Installation - Fuel shut-off valve ball controls 

MET: 76.20.00.501: Fuel shut-off valve ball controls: Adjustments and tests 

MET: 79.06.00.401: Oil system equipment: Removal - Installation 

MTC: 20.02.01.102: Identification of electrical equipment 

MTC: 20.02.01.103: Installation of pipes 

MTC: 20.02.01.402: Installation of "ARSAERO" unions 

MTC: 20.02.01.408: Installation of BNAé cylindrical couplings 

MTC: 20.02.05.404: Joining by bolts and nuts 

MTC: 20.02.05.406: Installation of wide-band jubilee clip clamps 

MTC: 20.02.06.402: Safetying with lockwire 

MTC: 20.02.07.401: Bonding procedure 

MTC: 20.02.07.402: Bonding procedure applied on metal structure 

MTC: 20.04.01.402: Cleaning of removed individual parts with liquid solvents 

MTC: 20.05.01.222: Application of PR 1771 B2 sealant 

MTC: 20.07.02.211: Storage, handling and installation of pyrotechnic devices 

ALERT SERVICE BULLETIN: 26.00.09. 

1.L. DOCUMENTS AFFECTED 

The modification will be integrated in the following manuals: 

- Illustrated Parts Catalog (IPC), 

- Maintenance Manual (MET). 

These documents will be issued at a later date. 

1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS 

 Interchangeability: 

Pipes PRE and POST MOD 073990 are not interchangeable. 

 Mixability: 

Mixability of pipes PRE MOD and POST MOD 073990 is prohibited. 
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2. MATERIAL INFORMATION 

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT 

For any information concerning modification kits and/or components or for assistance, contact the Sales and 

Customer Relations Department. 

Airbus Helicopters 

Etablissement de Marignane 

Direction Ventes et Relations Client 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE 1 

On the purchase order, please specify the mode of 

transport, the destination and the serial numbers of the 

aircraft to be modified. 

NOTE 2 

For ALERT SERVICE BULLETINS, order by: 

Telex: HELICOP 410 969F 

Fax: +33 (0)4.42.85.99.96.

2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT 

Not applicable. 

2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT 

 Kits or components to be ordered for one helicopter or one assembly: 

Key Word Qty New 

P/N Item Former 

P/N Instruction 

 

Fire extinguishing 

pipes crossed 

connection kit 

including: 

1 355A07-3990-071 

Pipe, equipped, LH 1 355A59-0601-01 1 

Pipe, equipped, RH 355A59-0608-00 Scrap 

Pipe, equipped, RH 1 355A59-0607-01 2 355A59-0607-00 Scrap 

Pipe, equipped, LH 1 355A59-0602-01 3 355A59-0602-00 Scrap 

Pipe, nozzle, RH 1 355A59-0604-01 4 355A59-0604-00 Scrap 

Pipe, nozzle, LH 1 355A59-0617-01 5 

355A59-0603-00 

or 

355A59-0617-00 

Scrap 

 
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 Material to be ordered separately: 

As per Work Cards and Tasks mentioned in this ALERT SERVICE BULETTIN and list below: 

Key Word Qty New 

P/N Item Former 

P/N Instruction 

 

Nut 3 ASN52320BH050N 6 

 Products to be ordered separately: 

As per Work Cards and Tasks mentioned in this ALERT SERVICE BULETTIN and list below: 

Key Word Qty Product P/N CM Item 

 

Lockwire AR EN3628-0,8 8 

Sealant AR PR 1771 B2 9 

 

The products can be ordered separately from the INTERTURBINE AVIATION LOGISTICS company. 

Website: http://www.interturbine.com

 Telephone: +49.41.91.809.300 

AOG: +49.41.91.809.444 

2.D. MATERIAL TO BE RETURNED 

Not applicable. 
 ASB No. AS355-26.00.10 

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3. ACCOMPLISHMENT INSTRUCTIONS 

3.A. GENERAL 

- Read and comply with general instructions concerning electrical power generation as per MET 

Work Card 24.00.00.301. 

- Read and comply with the general instructions for hydraulic power as per MET 

Work Card 29.00.00.301. 

- Read and comply with the general instructions concerning mechanical assemblies as per MET 

Work Card 60.00.00.301. 

- Read and comply with instructions for identification of electrical installations as per MTC 

Work Card 20.02.01.102. 

- Read and comply with instructions for installation of pipes as per MTC Work Card 20.02.01.103. 

- Read and comply with instructions for installation of "ARSAERO" unions as per MTC 

Work Card 20.02.01.402. 

- Read and comply with instructions for installation of BNAé cylindrical couplings as per MTC 

Work Card 20.02.01.408. 

- Read and comply with general instructions for joining by bolts and nuts as per MTC 

Work Card 20.02.05.404. 

- Read and comply with instructions for installation of wide-band jubilee clip clamps as per 

MTC Work Card 20.02.05.406. 

- Read and comply with instructions on safetying with lockwire as per MTC Work Card 20.02.06.402. 

- Read and comply with the bonding procedure as per MTC Work Cards 20.02.07.401 and 20.02.07.402. 

- Read and comply with instructions for cleaning removed detail parts with liquid solvents as per MTC 

Work Card 20.04.01.402. 

- Read and comply with instructions for use of PR 1771 B2 sealant as per MTC Work Card 20.05.01.222. 

- Read and comply with instructions for storage, handling and installation of pyrotechnic devices as per 

MTC Work Card 20.07.02.211. 

3.B. OPERATIONAL PROCEDURE 

- For helicopters which complied with ALERT SERVICE BULLETIN 26.00.09 and which embodied 

modification 355A088608.00 (these helicopters have the crossed connected squibs), comply with 

paragraphs 3.B.1., 3.B.2.a., 3.B.2.b. and 3.B.2.c.1., 3.B.3. 

- For helicopters which only complied with paragraph 3.B.2. of ALERT SERVICE BULLETIN 26.00.09 (these 

helicopters have a label on the instrument panel), comply with paragraphs 3.B.1., 3.B.2.a., 3.B.2.b., and 

3.B.2.c.2., 3.B.3. 

- For helicopters which did not comply with ALERT SERVICE BULLETIN 26.00.09, comply with paragraphs 

3.B.1., 3.B.2.a., 3.B.2.b., 3.B.2.c.2. (not including removal of the label from the instrument panel) and 3.B.3. 
 ASB No. AS355-26.00.10 

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3.B.1. Preliminary steps 

- On control panels "5 ALPHA 1" and "5 ALPHA 2", make sure that push-buttons "FIRE EXT 1" and "FIRE 

EXT 2" are not pressed. 

- Disconnect all electrical supply sources as per MET Work Card 24.00.00.301. 

- Install suitable access means. 

- Remove MGB-engine cowlings as per MET Work Card 53.00.00.403. 

- Disconnect the VHF antenna connector "28R" and remove the rear cowling. 

- Remove and/or open all cowlings, panels, doors and all equipment to allow adequate access to the various 

work areas. 

- Remove, if necessary, the hoist arm as per MET Work Card 25.63.00.401. 

- Remove the engine exhaust pipes as per MET Work Card 71.06.00.401. 

- Disconnect the ball controls of the fuel shut-off valve near the valve as per MET Work Card 76.20.00.401. 

- Remove the median and rear firewalls. 

- Drain the lubricating system of the LH and RH engines. 

- Remove the lubricating system outlet pipes of the engine as per MET Work Card 79.06.00.401. 

- Remove the P2 system pipes at the engine outlet as per MET Work Card 21.20.00.401. 

 RH side transmission support platform 

P2 system pipe to be 

removed 

Lubricating system outlet pipe 

to be removed 

Ball control to 

be removed 
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 LH side transmission support platform 

- For helicopters POST MOD OP1684, which previously drained the hydraulic system, disconnect the return 

pipe of the ground power receptacle system. 

 Combiner gearbox viewed looking forward

P2 system pipe to 

be removed 

Lubricating system outlet pipe 

to be removed 

Ball control to 

be removed 

Return pipe of the ground 

power receptacle system to be 

disconnected 
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3.B.2. Procedure 

3.B.2.a. Removal of the fire extinguishing system 

3.B.2.a.1. Removal of clamps and electrical harnesses (Figure 1) 

- Remove the squibs as per MET Work Card 26.20.00.401. 

- Remove nuts (o), washers (m) and (n), bolts (p), clamps (j) and spacers (k) located on the 

transmission support platform (Detail B). 

- Remove bolts (q), washers (h), (m) and (n), clamps (j) and spacers (k) located on the rear structure 

floor (Detail C). 

- Mark the routing of harnesses (w) and (x) (not shown in figure 1) on nozzle pipes (e) and (f) (see photo 

below). 

- Remove clamps (v) (not shown in figure 1) that attach harnesses (w) and (x) (not shown in figure 1) to 

nozzle pipes (e) and (f) (see photo below). 

 Reinforcement of the rear transmission bearing 

- Retain nut (o), washers (h), (m) and (n), bolts (p) and (q), clamps (j) and (v) and spacers (k). 

3.B.2.a.2. Removal of fire extinguishing system pipes (Figures 1 and 3) 

- Cut and remove the lockwire on the side of check valves (g) and on the side of exhaust nozzles (y) 

and unions (z) (DETAIL D Figure 1). 

- Disconnect and remove nozzle pipes (e) and (f) (DETAIL A Figure 1). 

- Scrap nozzle pipes (e) and (f). 

- Remove, if necessary, union (z) and nozzle (y) of the firewall (DETAIL D Figure 1). 

- Cut and remove the lockwire on the side of the fire extinguishing cylinders (DETAIL A Figure 1). 

- Disconnect pipe (c) on the side of the RH cylinder and pipe (a) on the side of the LH cylinder (DETAIL 

E Figure 3). 

- Remove pipes (a) and (c) fitted with check valve (g). 

- Disconnect pipe (d) on the side of the RH cylinder and pipe (b) on the side of the LH cylinder. 

- Remove pipes (b) and (d) fitted with check valve (g). 

- Cut and remove lockwire of check valves (g) (DETAIL A Figure 1). 

- Disconnect and scrap pipes (d) and (b) and remove check valve (g). 

v 

v 

e 

f 

w 

x 
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3.B.2.a.2. Removal of fire extinguishing system pipes (Continued) 

- Disconnect pipes (a) and (c) and remove check valve (g). 

NOTE 1 

Identify pipe (a), using a felt pen, before removal in order not 

to confuse it with pipe (d). 

- Scrap pipe (c). 

- If necessary, blow removed pipe (a) with dry air. 

- Retain pipe (a) and check valves (g). 

NOTE 2 

Put a blanking plug on each end of pipe (a). 

- Remove the fire extinguishing cylinders as per MET Work Card 26.20.00.402. 

3.B.2.b. Installation of fire extinguishing system pipes (Figure 2) 

NOTE 3 

Only remove blanking plugs when you connect pipes. 

3.B.2.b.1. Check of check valves 

- Manually press each valve (for memory 2 pistons per check valve). 

- Make sure pistons correctly move back to their seats as soon as thrust is released. 

- Visually check that there is no corrosion on the seats and pistons. 

3.B.2.b.2. Installation of nozzle pipes (Figure 2) 

- Install unions (z) and nozzles (y) of the firewall, if they were removed in paragraph 3.B.2.a.2. 

(Detail D). 

CAUTION 

PAY SPECIFIC ATTENTION WHEN POSITIONING 

NOZZLE PIPES (4) AND (5) ON THE 

REINFORCEMENT. ANY EXCESSIVE LOAD COULD 

DAMAGE THEM. 
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3.B.2.b.2. Installation of nozzle pipes (Continued) 

- Install nozzle pipes (4) and (5) on the transmission support platform (Detail A). 

NOTE 4 

It is preferable to keep the packaging of nozzle pipes (4) and 

(5) in order to protect them when they are positioned to 

prevent damage to their protection. Remove their 

packagings, once nozzle pipes (4) and (5) are installed. 

NOTE 5 

Make sure that nozzle pipes (4) and (5) are correctly routed 

along the reinforcement (see photo below). 

Reinforcement of the rear transmission bearing 

- Check correct positioning of drain orifices that must be positioned at the lower part on the pipes. 

- Ensure electrical bonding as per details B and C 

NOTE 6 

On nozzle pipes (4) and (5), provide for a paint free area on 

clamps (j) to ensure electrical bonding. 

- Ensure electrical bonding of all clamps (j). 

- Install clamps (j), spacers (k), washers (m) and (n), and bolts (p) as per Detail B. 

- Tighten bolts (p) to standard torque. 

- Perform the sealing on washers (n) using sealant (9). 

- Install clamps (j), spacers (k), washers (h), (m) and (n), bolts (q) and nuts (6) as per Detail C. 

- Tighten nuts (6) to standard torque. 

- Perform the sealing on washers (n) using sealant (9). 

- Attach harnesses (w) and (x) to nozzle pipes (4) and (5) using clamps (v) (not shown in figure 2) in the 

same way as the routing recorded in paragraph 3.B.2.a. 

Reinforcement 

4 

5 
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3.B.2.b.3. Check of the control system of the fire extinguishing system (Figure 2) 

- Remove the push-button covers as per MET Work Card 26.20.00.403. 

- Energize the aircraft electrical circuit as per MET Work Card 24.00.00.301. 

- Make sure there is voltage between terminals 1 and 3, and 2 and 3 of connector "14W1", by pressing 

button "FIRE EXT 1" of engine 1. 

- Make sure there is voltage between terminals 1 and 3, and 2 and 3 of connector "13W1", by pressing 

button "FIRE EXT 2" of engine 1. 

- Make sure there is voltage between terminals 1 and 3, and 2 and 3 of connector "14W2", by pressing 

button "FIRE EXT 1" of engine 2. 

- Make sure there is voltage between terminals 1 and 3, and 2 and 3 of connector "13W2", by pressing 

button "FIRE EXT 2" of engine 2. 

- De-energize the aircraft electrical circuit as per MET Work Card 24.00.00.301. 

- Install the push-button covers as per MET Work Card 26.20.00.403. 

3.B.2.b.4. Check of fire extinguishing cylinders 

- Check the presence of marking and identification labels. 

- Check the pressure recorded on the pressure gage at the considered temperature. 

NOTE 7 

Refer to the correspondence table of pressure-temperature 

located on the cylinder. 

3.B.2.b.5. Installation of pipes and valves (Figure 3) 

- On table: 

 Connect, without tightening, pipes (a) and (1) to check valve (g) (SECTION F-F), 

 Connect, without tightening, pipes (2) and (3) to check valve (g) (SECTION G-G), 

- Install pipes (a) and (1) fitted with check valve (g) and pipes (2) and (3) fitted with check valve (g) on 

nozzle pipes (4) and (5) (DETAIL E). 

- Blow pipe (a) with dry air to make sure exhaust nozzle (y) located on the RH side properly flows. 

- Blow pipe (1) with dry air to make sure exhaust nozzle (y) located on the RH side properly flows. 

- Blow pipe (2) with dry air to make sure exhaust nozzle (y) located on the LH side properly flows. 

- Blow pipe (3) with dry air to make sure exhaust nozzle (y) located on the LH side properly flows. 

- Install the fire extinguishing cylinders as per MET Work Card 26.20.00.402. 

- Make sure drain orifices are properly positioned. 

- Tighten all unions of pipes (a), (1), (2), (3), (4) and (5) as per MTC Work Card 20.02.01.103. 

- Safety the unions of pipes (a), (1), (2), (3), (4) and (5) with lockwire (8). 
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3.B.2.c. Cancellation of ALERT SERVICE BULLETIN 26.00.09. 

3.B.2.c.1. Helicopter POST MOD 355A088608.00: crossed connection of squibs (Figure 3) 

- Remove the yellow adhesive from pipe (a), that was affixed during compliance with ALERT SERVICE 

BULLETIN 26.00.09. 

- For the LH fire extinguishing cylinder: 

 Install grey squib (r) on the grey firing head and connect connector "13W2" as per 

MET Work Card 26.20.00.401 and SECTION F-F of Figure 3. 

 Install yellow squib (s) on the yellow firing head and connect connector "14W1" as per 

MET Work Card 26.20.00.401 and SECTION G-G of Figure 3. 

- For the RH fire extinguishing cylinder: 

 Install yellow squib (t) on the yellow firing head and connect connector "14W2" as per 

MET Work Card 26.20.00.401 and SECTION F-F of Figure 3. 

 Install grey squib (u) on the grey firing head and connect connector "13W1" as per 

MET Work Card 26.20.00.401 and SECTION G-G of Figure 3. 

Removed fire extinguishing cylinders 

Installed fire extinguishing cylinders 

Yellow Grey 

Yellow 

Yellow 

Grey 

Grey 

a 

2

1

1
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3.B.2.c.2. Helicopter PRE MOD 355A088608.00: label affixed to the instrument panel 

- Remove the label located on the instrument panel and that was affixed during compliance with ALERT 

SERVICE BULLETIN 26.00.09. 

- Install the squibs as per MET Work Card 26.20.00.401. 

3.B.3. Final steps 

- Install the P2 system pipes removed in paragraph 3.B.1. as per MET Work Card 21.20.00.401. 

- For helicopters POST MOD OP1684: 

 connect return pipe of the ground power receptacle system, RH side. 

 fill and drain hydraulic reservoir as per MET Work Card 12.00.00.308. 

- Install the lubricating system outlet pipe of the LH engine, removed in paragraph 3.B.1., 

as per MET Work Card 79.06.00.401. 

- Connect the ball controls of the fuel shut-off valve near the valve as per MET Work Card 76.20.00.401. 

- Install the median and rear firewalls. 

- Install the engine exhaust pipes as per MET Work Card 71.06.00.401. 

- Adjust the ball controls of the fuel shut-off valve as per MET Work Card 76.20.00.501. 

- Perform the final steps of the engine lubricating system as per MET Work Card 79.06.00.401. 

- Connect VHF antenna connector "28R". 

- Install the hoist arm as per MET Work Card 25.63.00.401, if removed in paragraph 3.B.1. 

- Install and/or close all cowlings, panels, doors and equipment removed and/or opened during preliminary 

steps (paragraph 3.B.1.). 

- Install the MGB-engine cowlings as per MET Work Card 53.00.00.403. 

- Remove access means. 

- Connect all electrical supply sources as per MET Work Card 24.00.00.301. 

3.C. IDENTIFICATION 

 Identification of this document: 

Record compliance with this ALERT SERVICE BULLETIN with the revision number in the aircraft 

documents. 

 Identification of modifications in the documentation: 

Record embodiment of modification 073990 in the aircraft documents. 
 ASB No. AS355-26.00.10 

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3.D. OPERATING AND MAINTENANCE INSTRUCTIONS 

 Operating instructions: 

Not applicable. 

 Maintenance instructions: 

Compliance with this ALERT SERVICE BULLETIN renders MET Work Card 26.20.00.401 applicable, without 

restriction. 

The Maintenance Manual (MET) will incorporate the instructions mentioned in paragraph 3.B.2.b. in a further 

revision. After incorporation of these instructions in the Maintenance Manual (MET) (Work Card 

26.20.00.404), refer to it. 
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PAGE LEFT BLANK INTENTIONALLY
ASB No. AS355-26.00.10 

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Figure 1

PRE MOD 073990

r 

s 

a b 

h j k m n o q 

13W2

14W1

e or f 

z 

y 

j 

q 

o 

h 

n 

k 

m 

n 

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Figure 2 

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See Fig 3 

See Fig 3 
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Figure 3 

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