MSB1078-186/1 

Page 1 of 5 

08 March 2012 

Replaces Issue: 15. Feb 2012

1078-186_1 MSB, Inspection of elevator trim tab arm Rev.1 G 115E/EG 

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies 

SERVICE BULLETIN NO. MSB1078-186/1 

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:

Next 50 hours inspection or next regular inspection whichever comes first. 

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 an 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. 

Fig. 1 

Location of crack
MSB1078-186/1 

Page 2 of 5 

08 March 2012 

Replaces Issue: 15. Feb 2012

1078-186_1 MSB, Inspection of elevator trim tab arm Rev.1 G 115E/EG 

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies 

Dye penetrant check of defective items revealed, that a visual inspection of an installed item 

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 is mandated 

by this MSB1078-186/1. This measure will ensure safe operation until a terminating action is 

mandated by a later revision of this Service Bulletin. 

Note: If the affected item has been already replaced while accomplishing MSB1078-186, the 

instructions in 1.8 of MSB1078-168/1 may be considered as accomplished. 

1.6 Concurrent documents:

G 115E: AMM TR No. 05-21 

G 115EG: AMM / JG TR No. 05SMC-03, 05SMC-04, 05GV-04 

1.7 Approval Note:

The technical content of this document is approved under the authority of EASA Design 

Organization Approval No. EASA.21J.030. 

1.8 Accomplishment/ Instructions

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 signs 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) by removing nut, washer and bolt (item 20, 30, 40)
MSB1078-186/1 

Page 3 of 5 

08 March 2012 

Replaces Issue: 15. Feb 2012

1078-186_1 MSB, Inspection of elevator trim tab arm Rev.1 G 115E/EG 

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies 

10 

20

30

40

Left Elevator

Fig. 3 

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

1.8.6 If no crack is found, clean trim tab bracket and proceed with 1.8.8

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 aircraft S/N and flight hours. 

1.8.8 Install trim tab arm P/N 115E-3758 (item 10) using bolt, washer and new locking nut 

(item 20, 30, 40). Apply correct torque value I.A.W. G 115E AMM chapter 20-10 and 

G 115EG Job Guide in analogy. 

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 in 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 procedures and regulations. 

1.9 Repetitive Actions

Repeat special inspection in para 1.8 every 500FH until the terminating action is accomplished. 

For regular inspection refer to G 115E AMM, Chap. 05-20, para. 10 and G 115EG Job Guide in 

analogy. 
MSB1078-186/1 

Page 4 of 5 

08 March 2012 

Replaces Issue: 15. Feb 2012

1078-186_1 MSB, Inspection of elevator trim tab arm Rev.1 G 115E/EG 

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies 

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 1 

2 LN9348-05 Lock Nut 4 

3 LN9348-06 Lock Nut 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/A 
MSB1078-186/1 

Page 5 of 5 

08 March 2012 

Replaces Issue: 15. Feb 2012

1078-186_1 MSB, Inspection of elevator trim tab arm Rev.1 G 115E/EG 

Grob Aircraft AG, Lettenbachstrasse 9, D-86874 Tussenhausen-Mattsies 

III. REMARKS

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 1056/2008) 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 address of the new owner as well as with 

the respective serial number. 

For questions and assistance please contact: 

 Rudi Vodermeier, Head of Customer Service & Support, 

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-115.html

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