MSB1121-144 Page 1 of4 14 July 2014 Replaces Issue: 

### AI RCR A FT 

# S E RVICE BULLETIN NO. M S B1121-144 I. TECHNICAL DETAILS 1 . 1 Category : Man d atory Note : GROB issues Service Bu ll etins of category Mandatory ( MSBs) , if the i nformation or i nstructions have a safety intent either re l ated to design or co nformity and to publish revisions of manuals (AFM, AMM, IPC) . However, accord i ng to Article 20 (1) of Regulation (EC) No. 216/2008, only EASA may issue mandatory information , in the form of an Airworthiness Directive (AD) , in order to react to a g iven safety problem . Service Bullet i ns classified Mandatory issued by GROB's des ign organisation do not have a lega l ly mandatory c haracter equ iva le nt to an AD , cannot have enforcement i mp li cations and , th erefore , serve as i nformati on or i nstruction by GROB on ly . T h is a lso appl ies to cases where a Service Bulletin is published in anticipation of an AD . Note: Th is service bulletin is issued i n ant icipation of an AD . Issue of a n AD wi ll not necessaril y lead to revision of thi s service bu ll et i n . 1 . 2 Airplanes affected: G 120A all SIN G 120A - I all SIN 1.3 Time of Compliance: Part 

### A: Before next I F R or VFR N ig ht flight , or with i n next 50FH , wh ichever comes first. 1.4 Subject: AT A-Code : 80-00 Starting Inspection of starter solenoid 1 . 5 Reason: Grob rece ived a report about a tota l loss of electrical power i n IMC on a G 115E a i rcraft . Root cause was found to be a defect starter sole no id . The starter soleno id had an i nterna l defect causing a short circu it. The defect cannot be detected by visual i nspection. The i nstallation is similar to the i nstallation on G120 aircraft . This Service Bulletin is i ntended to prevent an unsafe condition . The configurat ion of the aircraft is not affected by this Service Bulletin. 1.6 Concurrent documents: Corresponding AMM 1.7 Approval Note : The technical conten t of this document is approved under the authority of EASA Design Organization Approval No . EASA21J . 030 .

1 1 21 ·1 44 M$8, Inspection of start., sole ncid 

# G 120A, A-1 Grob Aircraft AG , Lettenbachstrasse 9, D-86874 Tussenhausen-MattsiesMSB1121-144 Page 2 of 4 14 July 201 4 Replaces Issue : 1.8 Accomplishment/Instructions Part A One-time Inspection 1.8.1 Disconnect the aircraft battery , refer to AMM Chapter 24-31. 1 . 8 .2 Remove the Engine Cowlings, refer to AMM Chapter 71 - 10. 

### AIRCRAFT

1 . 8 . 3 Visually inspect the starter. Make sure that the power connection bolts have the same len gth , refer to Figure 1 for defective item and Figure 2 for correct installation.

Fi gure 1 : Incorrect connection bo lts Figure 2: Correct installati on 1.8.4 Release the two bolts on the starter solenoid . Carefully pull the solenoid away from the starter housing until the dead stop . Make sure that the solenoid plunger is still attached , refer to Figure 3. Attach the solenoid to the starter w ith the two bolts .

Figure 3 : Starter soleno id at dead stop 1.8. 5 If the starter is OK , do step 1.8. 7 . 1 . 8.6 If the starter is not OK or in case of doubt , replace the Starter. 

# G 120A, A- 1 Grob Aircraft AG , Lettenbachstrasse 9, D-86874 Tussenhausen-Matts iesMSB1121-144 Page 3 of4 14 July 2014 Replaces Issue: 1.8.7 Install the Engine Cowlings , refer to AMM Chapter 71 - 10. 1. 8. 8 Connect the a i rcraft battery , refer to AM M Chapter 24-31 . 

### A IR CRAFT

1 . 8.9 Release aircraft into service according to national requirements. PartS Reserved for the terminating action 1.9 Repetitive Actions none 

### II. PLANNING INFORMATION 2.1 Weight and CG 

### N/A 2.2 Material and Availability 

### N/A 2.3 Special Tools 

### N/A 2 . 4 Labor costs 

### N/A 2.5 Reference documents Correspondi ng AMM and IPC 2.6 Credit 

### N/A

1121-144 M$8, Inspection olslalter solenoid 

# G 120A, A - 1 Grob A i rcraft AG, Lettenbachstrasse 9, D-8687 4 Tussenhausen-MattsiesMSB 1 121-144 Page 4 of4 14 July 2014 Replaces Issue: 

## Ill. REMARKS 

# 0 AIRCRAFT The instructions in paragraph 1.8 have to be accomplished and certified in the logbook by authorized staff:

- in EASA countries according to Article 5 VO EG 2042/03 (VO EG 1 056/2008) Appendix Ill - Part 66

- in non-EASA countries according to national regulations with respect to maintenance. If you have sold your ai rcraft i n the meantime , we kindly ask you to forward this information to the new owner and to provide us with the name and address of the new owner as well as with the respective serial number. For questions and assistance please contact: phone : fax : e-mail :

1 12 1 · 144 MS8. 1 nspeetion of starter soleno : d Product Support , +49 8268 998105 +49 8268 998200 productsupport@grob-aircraft.com



# G 120A, A- 1 Grob Airc raft AG , Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies