EASA AD No.: 2010-0107 

EASA Form 110 Page 1/3 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2010-0107 

Date: 11 June 2010 

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with Regulation 

(EC) No 216/2008 on behalf of the European Community, its Member States and of the European 

third countries that participate in the activities of EASA under Article 66 of that Regulation. 

This AD is issued in accordance with EC 1702/2003, Part 21A.3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the 

continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may operate an 

aircraft to which an AD applies, except in accordance with the requirements of that AD, unless otherwise specified by the Agency [EC 

2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exemption]. 

Type Approval Holder’s Name: 

GROB AIRCRAFT AG 

Type/Model designation(s): 

G 103 C Twin III SL Powered Sailplanes 

Approval Number: Germany No. 869 

Foreign AD: Not applicable 

Supersedure: None 

ATA 61 Propellers - Propeller Assembly – Inspection / Repair 

Manufacturer(s): Grob Aircraft AG (formerly Grob Aerospace GmbH, Grob Luft- & Raumfahrt 

GmbH) 

Applicability: G 103 C Twin III SL powered sailplanes, all serial numbers. 

Reason: The in-flight loss of a propeller and pulley wheel from the engine of a Grob 

G 103 C Twin III SL powered sailplane has been reported. 

Grob Aircraft AG suspects that the possible reasons for this loss can be due to 

an incorrect propeller track (the play at the propeller tip) and/or to a damaged 

propeller nut securing plate. 

Those conditions, if not corrected, could also result in loosening of parts and, 

consequently could result in damage to the sailplane and possible injury to 

persons on the ground. 

For the reasons stated above, this AD requires to inspect the propeller assembly 

attachment, to verify that the propeller track is within the allowable tolerances 

and, depending on findings, to accomplish the relevant corrective actions. 

Effective Date: 25 June 2010 
EASA AD No.: 2010-0107 

EASA Form 110 Page 2/3 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) Within 30 days after the effective date of this AD, accomplish the following 

actions concurrently: 

(1.1) Update the aircraft documentation (Flight Manual and Maintenance 

Manual) in accordance with Grob Aircraft Service Bulletin (SB) No. 

MSB 869-24/1. 

(1.2) Inspect for cracks the bent area of the engaged tooth of the propeller 

nut securing plate. 

(1.3) Verify that the propeller track (the play at the propeller tip) is within the 

allowable tolerances in accordance with the updated technical 

documentation (the list of documentation instructions is provided in the 

Grob Aircraft Service Letter (SL) No. SL-869-01). 

Note 1: The torque values and tolerances of the propeller assembly attachment 

nut have been standardised in the Flight and Maintenance Manuals. 

(2) If the bent area of the engaged tooth of the propeller nut securing plate has 

no crack but the propeller track value measured is not within the allowable 

tolerances, before next flight, readjust the torque of the propeller attachment 

nut in accordance with the updated aircraft technical documentation (the list 

of documentation instructions is provided in the Grob Aircraft SL 

No. SL-869-01). 

(3) If any crack is found in the bent area of the engaged tooth of the propeller 

nut securing plate, before next flight, accomplish the following actions 

concurrently: 

(3.1) Remove the propeller attachment nut and thereafter bend another 

tooth (not an already bent tooth) of the securing plate to secure the 

propeller nut. 

 It is not allowed to bend an already bent tooth. If all teeth of the 

securing plate have been already bent, replace the securing plate with 

a serviceable one. 

(3.2) Screw back the propeller attachment nut (and its securing plate) and 

tighten it, applying the torque as defined in the updated aircraft 

technical documentation (the list of documentation instructions is 

provided in the Grob Aircraft SL No. SL-869-01) and verify accordingly 

that the propeller track is within the allowable tolerances. 

Note 2: The action required by paragraph (1) of this AD may also be 

accomplished by a Part-66 qualified person in accordance with M.A. 801 (b)2. 

Ref. Publications: Grob Aircraft AG Service Bulletin No. MSB-869-24/1 dated 20 July 2009. 

Grob Aircraft AG Service Letter No. SL-869-01 dated 9 June 2009. 

The use of later approved revisions of these documents is acceptable for 

compliance with the requirements of this AD. 

Remarks: 1. If requested and appropriately substantiated, EASA can approve Alternative 

Methods of Compliance for this AD. 

2. The required actions and the risk allowance have granted the issuance of a 

Final AD with Request for Comments, postponing the public consultation 

process after publication. 

3. Enquiries regarding this AD should be referred to the Airworthiness 

Directives, Safety Management & Research Section, Certification 

Directorate, EASA. E-mail ADs@easa.europa.eu. 
EASA AD No.: 2010-0107 

EASA Form 110 Page 3/3 

4. For any question concerning the technical content of the requirements in 

this AD, please contact: Grob Aircraft AG; Lettenbachstr. 9; TussenhausenMattsies; Head of Customer Service & Support, Germany 

Telephone: +49 (0) 8268 998 139, Fax: +49 (0) 8268 998 200 

E-mail: productsupport@grob-aircraft.com, Website: www.grob-aircraft.com

and/or www.firecmm.com.