Berbeda dengan airworthiness directives (AD) yang berupa perintah dari pabrik yang merupakan keharusan untuk dilakukan karena bisa, sudah atau akan mengancam keselamatan, maka sebuah Service Bulletin (SB) adalah rekomendasi dari pabrik untuk melakukan sebuah prosedur/perbaikan/penggantian suku cadang untuk menanggulangi kerusakan baik yang berasal dari pabrik, atau pencegahan kerusakan karena sebab lain.

Sebuah SB menjadi wajib untuk dikerjakan jika ada AD di dalam prosedurnya.

Jika SB bukanlah sebuah kewajiban kenapa pabrik mengeluarkan SB? Alasan utamanya adalah keamanan (safety). Sebuah prosedur yang ditulis di SB memang tidak wajib, tapi kalau bisa dikerjakan kenapa tidak? Mengerjakan SB membuat sebuah pesawat menjadi lebih aman.

Resiko yang harus ditanggung pemilik pesawat pada waktu menjalankan sebuah SB adalah biaya. Dengan alasan ini banyak pemilik/operator pesawat yang memilih untuk tidak mengerjakan prosedur SB.

Mengerjakan sebuah prosedur SB selain membebani dengan biaya pengerjaan, juga mungkin akan berhubungan dengan biaya pembelian suku cadang.

Kalau saja ada akses informasi maskapai apa saja yang menjalankan SB dan yang tidak menjalankan, saya akan memilih maskapai penerbangan yang rajin menjalankan SB dari pabrik.

Berikut ini tata-cara penerbitan SB berdasarkan AC 21-99 yang bisa diunduh di website Departemen perhubungan



1. Regulatory Reference
CASR A 21-Paragraph 21-99, “Required design changes”
CASR Part A39, “Airworthiness Directive”

2. Definitions

  • (a). Service Bulletin is the document prepared by the manufacturer of a product or  appliance to provide technical information on changes to the type design to the  product or appliance. It may also provide technical information on inspections  and repairs to be applied on a product or appliance. A service bulletin is used to  transmit actions which require a record of accomplishment. A service bulletins is made available to all operators of the product or appliance. 
  • (b). Service Letter is the document prepared by the manufacturer of a product or appliance to provide information or to request service information from the operator of the product or appliance. Changes to the type design and actions  that require a record of accomplishment are not included in service letters, but are subjects to service bulletins.
  • (c). Product is an aircraft, aircraft engine or propeller. 
  • (d). Appliance is defined as any instrument, mechanism, equipment, part,  apparatus, appurtenance, or accessory, including communications equipment,  that is used or intended to be used in operating or controlling an aircraft in  flight, is installed in or attached to the aircraft, and is not part of an airframe,  engine, or propeller. 


3. Approval
All service bulletins are reviewed and approved by DGCA. DGCA approval of a  service bulletin can only been granted after DGCA approval of the corresponding  changes to type design, inspection method or repair.
Service bulletins must be approved by the DGCA prior to their distribution to operators.
Service letters do not address embodiment of changes to type design, inspection or repair and therefore are not approved by the DGCA.


4. Classification

Service bulletins are classified in three categories

  • (a) Mandatory : When an unsafe conditions is discovered, a mandatory service  bulletins is issued in accordance with CASR 21-99 and CASR Part A39 to  correct the unsafe condition. These service bulletins are covered by an  Airworthiness Directive (AD) as required by CASR A39. When the unsafe  condition requires immediate action from the operators, mandatory service  bulletin is released by telegraph or fax. 
  • (b) Recommended : When a failure or disfunctioning may reduce the level of  safety of the product or appliance without generating an unsafe condition as  defined per CASR Part A39 or, when change in type design can contribute to  the safety of the product or appliance. 
  • (c) Optional : When the service bulletin is not mandatory or recommended. 

5. Responsibilities

  • (a) It is the responsibility of the manufacturer to develop release and update service bulletins in order to provide the operators of the product with the necessary information to maintain or improve the safety of the product. All service bulletins including their revisions must be approved by DGCA before their distribution to the operators. 
  • (b) Service Bulletins shall be practical from the operator’s stand point, i.e. they shall not required new parts when old parts may be repaired or reworked, but  shall, wherever practicable, include instruments and lists of new parts to allow the operator to select either method. 
  • (c) Review of the technical content and approval of service bulletin is the responsibility of the DGCA specialist in the Certification Team responsible for the certification or approval of the product. When necessary the Project Manager (PM) will assist to ensure that adequate coordination within the certification team and other Sub Directorate is accomplished. 
  • (d) The classification of service bulletin is proposed by the manufacturer to DGCA, who may accept the classification or, if necessary required a change to the classification. 

6. Publication

  • (a) Separate service bulletins shall be issued to cover each subject and shall describe changes that fall into the following categories : 
    • 1. Modification to the aircraft, engine, accessory including embedded software. Including modifications which affect performance, improve reliability, increase safety or operation, provide improved economy or facilitate maintenance or operation. 
    • 2. Substitution of one part with another superseding part only when it is not completely interchangeable both functionally and physically, or when the change is considered to be sufficiently urgent or critical that special scheduling or record of accomplishment will be required. 
    • 3. Substitution of one embedded software program by another which changes equipment function and the part number of the programmed memory device, requiring a record of accomplishment. 
    • 4. Special inspections or checks required to maintain the aircraft, engine, or accessories in safe operating condition. 
      • (i) One time inspections or checks to detect a flaw or manufacturing error. 
      • (ii) Special inspections or checks required to be performed until a corrective action can be taken. The modification information may be issued as a revision to the same service bulletin that transmits the inspection instructions. 
      • (iii) Special functional checks of an urgent nature required to detect an incipient failure, such as pressure checks, functional checks, etc. 
    • 5. Reduction of existing file limits or establishment of first time life limits for components. 
    • 6. Conversions from one engine model to another. 
    • 7. Changes affecting the interchangeability or intermixability of parts. 
  • (b) Service Bulletins must not be used to cover routine recommended inspections or checks, standard repairs, or revisions to maintenance practices or shop procedures. These shall be covered as revisions to the manufacturer’s Maintenance, Structural Repair, or Component Maintenance Manual as appropriate. 
  • (c) Application of Standard Numbering System :
    1. The service bulletin number shall consist of a product or equipment identification number, ATA chapter number, issue sequence number. 
    2. For the printed media, each page shall bear the service bulletin number. The page number shall be placed immediately below the service bulletin number. In addition, the first page of the service bulletin shall state the total number of pages included in the complete service bulletin. ATA specification 100 chapter numbers must be used to identify the subject or discipline. 


Example : 

Service Bulletin :

CN235 – 25 – 0101
Page 1 of 12
Identification No : CN 235
ATA Chapter No : 25 (equipment/furnishing)
Order number : 0101 (101 Service Bulletins released to date for CN235 concerning equipment/furnishing)

  • (d) Service Bulletins should follow the format outlined in ATA specification 100 (chapter 2.7.4) as follows : 
    1. Planning Information 
      • (i) Effectivity (Type, model, version, serial number…) 
      • (ii) Concurrent Requirements 
      • (iii) Reason (purpose of the modification, replacement or inspection) 
      • (iv) Description 
      • (v) Compliance (Manufacturer’s recommendations for accomplishment) 
      • (vi) Approval (Statement from the Airworthiness Authority) 
      • (vii) Manpower (provided for general guidance in operators modification planning) 
      • (viii) Weight and Balance 
      • (ix) Electrical Load Data 
      • (x) Software Accomplishment Summary 
      • (xi) References 
      • (xii) Other Publication Affected
    2. Material Information 
      • (i) Material – Price and Availability 
      • (ii) Industry Support Information 
      • (iii) Material Necessary for Each Aircraft/Engine/Component 
      • (iv) Material Necessary for Each Space 
      • (v) Re – identified Parts 
      • (vi) Tooling – Price and Availability 
    3. Accomplishment Instructions. This section shall contain step-by-step instructions for accomplishing the work, as follows : 
      • (i) Section defining the conditions to apply the service bulletin (i.e. aircraft in maintenance status,…) 
      • (ii) Section detailing the different actions/operations to allow the embodiment of the modification, replacement or inspections. 
      • (iii) Section detailing the embodiment of the modification, replacement (i.e removed of previous parts and installation of new areas) or inspections. 
      • (iv) Section detailing all the checks or test that must be performed to control the functioning of the equipment, systems or parts affected by the service bulletin. 
      • (v) Section detailing the different actions to close the job concerning the 
      • application of the service bulletin. 
    4. Appendix, when applicable 
  • (e) Revisions : 
    1. When necessary the manufacturer must update the service bulletin. 
    2. This updating can be complete or partial and will be carried out by reissuing the affected pages. 
    3. A cover sheet must be attached to each updated issue of that service bulletin in order to clearly state the reason for the revision and the references of the previous revisions. 
    4. Service bulletin revisions shall be identified in the service bulletin number, for example : CN235-25-0101 Revision 1 

7. Service Bulletin Index
A list of all service bulletins (Service Bulletin Index) must be published and periodically updated by the manufacturer for each aircraft, aircraft engine and propeller type. The information released in the Service Bulletin Index will consist of service bulletin numbers, title/subject, effectivity, date of issue, revision numbers and dates of revisions.



Berikut ini adalah cuplikan dari sebuah SB untuk model pesawat tertentu:








Group A airplanes

The airplanes that follow that are equipped with the 0743631-1 Strut Tube Assembly:

NOTE: These airplanes were delivered from the factory with the 0743631-1 Strut Tube Assembly installed.



172R 17281534 thru 17281621

172S 172S10765 thru 172S11264

182T 18282121 thru 18282359

T182T T18208883 thru T18209094

Group B airplanes

The airplanes that follow that have replaced the strut tube assembly or have replaced the nose gear assembly:



172R 17280001 thru 17281533

172S 172S8001 thru 172S10764

182S 18280001 thru 18280944

182T 18280945 thru 18282120

T182T T18208001 thru T18208882



To make an improved nose gear strut tube assembly available.



This service bulletin provides parts and instructions to install the new nose gear strut tube assembly.



RECOMMENDED. This service bulletin should be accomplished at the next 200-hour or 12-month (annual-type) inspection.



Cessna received FAA approval for the technical data in this publication that changes the airplane type design.

Cessna received EASA approval for the technical data in this publication that changes the airplane type design.





Model 172 Series 1996 and On Maintenance Manual

Model 182/T182 Series 1997 and On Maintenance Manual



Model 172R & 172S Illustrated Parts Catalog

Model 182S/182T/T182T Illustrated Parts Catalog



1. Look at the airplane paperwork and see if the airplane has a 0743631-1 Nose Gear Strut Tube Assembly or a 0743621-9 Nose Gear Strut Tube Assembly installed.

A. If it has a 0743621-9 Nose Gear Strut Tube Assembly installed, go to Step 7.

B. If it has a 0743631-1 Nose Gear Strut Tube Assembly, go to Step 2.

C. If you cannot determine the part number of the installed nose gear strut tube assembly, do as follows:

(1) Touch a magnet to the cap at the top of the strut assembly.


NOTE: The 0743621-9 Nose Gear Strut Tube Assembly is made of steel and the 0743631-1 Nose Gear Strut Tube Assembly is made of Aluminum.

(a) If the magnet attaches to the cap, a 0743621-9 Nose Gear Strut Tube Assembly is installed. Go to Step 7.

(b) If the magnet does not attach to the cap, a 0743631-1 Nose Gear Strut Tube Assembly is installed. Go to Step 2.

2. Prepare the airplane for maintenance.

A. Make sure that the airplane is electrically grounded.

B. Make sure that all switches are in the OFF/NORM position.

C. Disconnect electrical power from the airplane.

(1) Disconnect the airplane battery.

(2) Disconnect external electrical power.

D. Attach maintenance warning tags to the battery and external power receptacle that have "DO NOT


3. Remove the 0743631-1 Nose Gear Strut Tube Assembly and save it for field scrap. (Refer to the applicable model maintenance manual, Chapter 32, Nose Landing Gear - Maintenance Practices.)

4. Look inside the shock strut tube assembly after you remove the old nose gear strut tube assembly from inside it, and if there is paint residue, remove the paint.


CAUTION: As you push the new 0743631-5 Nose Gear Strut Tube Assembly, with MS28775-225 O-ring attached, into the upper strut, make sure that you do no damage to the MS28775-225 O-ring.

5. Use a new MS28775-225 O-ring and new (model 172, MS21042L5 and MS21045L3) (model 182, MS21042L5 and MS21044N3) Nuts and install the 0743631-5 Nose Gear Strut Tube Assembly. (Refer to the applicable model maintenance manual, Chapter 32, Nose Landing Gear - Maintenance Practices.)

6. Remove the maintenance warning tags and connect the airplane battery.

7. Make an entry in the airplane logbook that states compliance and method of compliance with this service bulletin.


Model 172 and model 182 airplanes, order the parts below to install this modification.


Dan seterusnya…..