MSB1078-186/2

Page 1 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies 

# SERVICE BULLETIN NO. MSB1078-186/2

I. TECHNICAL DETAILS

1.1 Category:

Mandatory

1.2 Airplanes affected:

G 115E all S/N

G 115EG all S/N

1.3 Time of Compliance:

Part A: Next 50 hours inspection or next regular inspection whichever comes first , before receipt of material for terminating action.

Note: Replacement of an affected trim tab arm in accordan ce with the instructions of

MSB 1078-186 at original issue is acceptable to com ply with Part A of this Service

Bulletin.

Accomplishment of MSB 1078-186/1 is acceptable to c omply with Part A of this

Service Bulletin.

Part B: Terminating action: Next 50 hours inspectio n or next regular inspection whichever comes first, after receipt of material.

1.4 Subject:

ATA-Code: 55-20 Elevators and Trim tab Inspection of elevator trim tab arm

1.5 Reason:

Grob received a report from a fleet operator that a n elevator trim tab arm P/N 115E-3758 was found cracked from a rear mounting hole (either L/H or R/H) to the rear edge of the trim tab arm.MSB1078-186/2

Page 2 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies Fig. 1

Dye penetrant check of defective items revealed, th at a visual inspection of an installed item mandated with MSB1078-186 at original issue may not be sufficient to detect every crack on the bracket (Fig. 2).

Fig. 2

Therefore a dye penetrant check or more significant NDT of the dismounted parts has been mandated by MSB1078-186/1 to ensure safe operation until the terminating action will be accomplished.

Investigation of defective parts revealed corrosion cracking as cause for cracks. To prevent future cracking, the Trim Tab Arm 115E-3758 is repl aced by 115E-3758/1, which is manufactured from an alloy resistant to corrosion c racking. In addition to that, shaping is improved and a paint coat is applied.

1.6 Concurrent documents:

G 115E: AMM TR No. 05-21 G 115EG: AMM / JG TR No. 05SMC-03, 05SMC-04, 05GV-0 4 Location of crackMSB1078-186/2

Page 3 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies 1.7 Approval Note:

The technical content of this document is approved under the authority of EASA Design Organization Approval No. EASA.21J.030.

These information or instructions relate to change no. MÄM1078-161 which has been approved
under the authority of EASA Design Organisation App roval No. EASA.21J.030.

1.8 Accomplishment/ Instructions

Part A

1.8.1 Ensure that the aircraft is safe for parking I.A.W. G 115E AMM chapter 10-10 and G 115EG Job Guide in analogy.

1.8.2 Inspect elevator trim tab operating arm for s igns of cracking, especially both upper and lower surfaces from the rear bolt mounting holes to the rear of the operating arm.

1.8.3 Remove trim tab I.A.W. G 115E AMM chapter 55- 20 para. 3B and G 115EG Job Guide in analogy

1.8.4 Remove trim tab arm (item 10 in Fig. 3 ) by removing nut, washer and bolt (item 20, 30,

40 in Fig. 3 )

10 20

30

40 Left Elevator

Fig. 3

1.8.5 Perform dye penetrant check or more significa nt NDT on trim tab arm P/N 115E-3758

1.8.6 If no crack is found, clean trim tab bracket and proceed with 1.8.8MSB1078-186/2

Page 4 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies 1.8.7 If a crack is confirmed , the trim tab arm has to be replaced by a new item

.

Note: Any finding has to be reported to Grob with aircraf t S/N and flight hours.

1.8.8 Install trim tab arm P/N 115E-3758 using bolt , washer and new locking nut (item 20, 30,

40 in Fig. 3 ). Apply correct torque value I.A.W. G 115E AMM cha pter 20-10 and G 115EG Job Guide in analogy.

Note: In place of installing the original trim tab arm ac cording 1.8.8, you may proceed with

1.8.14 of Part B following receipt of new material.

1.8.9 Install trim tab I.A.W. G 115E AMM chapter 55 -20 para. 3C and G 115EG Job Guide in analogy

Note: Make sure, that the bolt holes of trim rods 3 are i n alignment with the trim arm and the bolts may be installed easily. If necessary adjust accordingly I.A.W. G 115E AMM chapter 27-31 para. B and G 115EG Job Guide in analogy.

1.8.10 Return aircraft to service as per relevant p rocedures and regulations.

Part B Terminating Action

1.8.11 Ensure that the aircraft is safe for parking I.A.W. G 115E AMM chapter 10-10 and G 115EG Job Guide in analogy.

1.8.12 Remove trim tab I.A.W. G 115E AMM chapter 55 -20 para. 3B and G 115EG Job Guide in analogy

1.8.13 Remove trim tab arm (item 10 in Fig. 3) by r emoving nut, washer and bolt (item 20, 30, 40 in Fig. 3)

1.8.14 Install new trim tab arm P/N 115E-3758/1 (item 4 of List 2.2) using bolt, washer and new locking nut (item 20, 30, 40 in Fig. 3). Apply corr ect torque value I.A.W. G 115E AMM chapter 20-10 and G 115EG Job Guide in analogy.

1.8.15 Install trim tab I.A.W. G 115E AMM chapter 5 5-20 para. 3C and G 115EG Job Guide in analogy

Note: Make sure, that the bolt holes of trim rods 3 are i n alignment with the trim arm and the bolts may be installed easily. If necessary adjust accordingly I.A.W. G 115E AMM chapter 27-31 para. B and G 115EG Job Guide in analogy.

1.8.16 Return aircraft to service as per relevant p rocedures and regulations.MSB1078-186/2

Page 5 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies 1.9 Repetitive Actions

Repeat special inspection in para 1.8 Part A every 200FH until the terminating action Part B is accomplished. For regular inspection refer to G 115E AMM, Chap. 0 5-20, para. 10 and G 115EG Job Guide in analogy.



## II. PLANNING INFORMATION

2.1 Weight and CG

N/A

2.2 Material and Availability

Item P/N Description Qty. / A/C

1 115E-3758 Trim Tab Arm (pre-modification) 1

2 LN9348-05 Lock Nut 4

3 LN9348-06 Lock Nut 1

4 115E-3758/1 Trim Tab Arm (post modification) 1

2.3 Special Tools

N/A

2.4 Labor costs

N/A

2.5 Reference documents

Corresponding AMM and IPC

2.6 Credit

N/AMSB1078-186/2

Page 6 of 6

28 March 2012 Replaces Issue: 08. Mar 2012

1078-186_2 MSB, Inspection of elevator trim tab ar m Rev.2 

# G 115E/EG

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tuss enhausen-Mattsies



## III. REMARKS

The instructions in paragraph 1.8 have to be accomp lished and certified in the logbook by

authorized staff:

- in EASA countries according to Article 5 VO EG 2042/03 (VO EG 1056/2 008) Appendix III –

Part 66

- in non-EASA countries according to national regulations with respect to maintenance.

If you have sold your aircraft in the meantime, we kindly ask you to forward this information to the new owner and to provide us with the name and a ddress of the new owner as well as with the respective serial number.

For questions and assistance please contact:

Rudi Vodermeier, Head of Customer Service & Suppo rt,

phone: +49 8268 998139

fax: +49 8268 998200

e-mail: productsupport@grob-aircraft.de

SB-Index: http://www.grob-aircraft.eu/service-and-support/g-1 15.html

Order: http://www.grob-aircraft.eu/service-and-support/gen eral/order-form.html