Airworthiness Directive · Amendment 39-14855 · Schempp-Hirth Flugzeugbau GmbH Model Duo Discus T Gliders
Schempp-Hirth Flugzeugbau GmbH Model Duo Discus T Gliders
This AD applies to Model Duo Discus T gliders, serial numbers 1 through 149, certificated in any category.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as the possible failure of the attachment of the propeller blades. This AD requires actions that are intended to address the unsafe condition described in the MCAI.
As of January 3, 2007 (the effective date of this AD), unless already done, do the following actions.
(1) For propellers with less than 15 hours time-in-service (TIS) as of the effective date of this AD:
(i) Prior to the first flight of each day, visually inspect the propeller hub in the area of the five propeller blade roots for cracks using a minimum 10x magnifier. If necessary, clean the hub before checking.
(ii) Prior to further flight after any crack is found or upon accumulating 15 hours TIS, whichever occurs first, remove the propeller hub and return to the propeller manufacturer for inspection and overhaul. Send the propeller hub along with the propeller hours time-in-service (TIS) to Technoflug Leichtflugzeugbau GmbH, Dr. Kurt Steim Strasse 6, D-78713 Schramberg.
(iii) You may remove the propeller hub and return as specified in paragraph (e)(1)(ii) of this AD at any time prior to accumulating 15 hours TIS on the propeller to terminate the inspection requirement of paragraph (e)(1)(i) of this AD.
(2) For propellers with 15 or more hours TIS as of the effective date of this AD: Prior to further flight, remove the propeller hub and return to the propeller manufacturer for inspection and overhaul. Send the propeller hub along with the propeller hours time-in-service (TIS) to Technoflug Leichtflugzeugbau GmbH, Dr. Kurt Steim Strasse 6, D-78713 Schramberg.
(3) For all sailplanes: With the propeller removed, the powered sailplane can temporarily be used in the sailplane configuration. If the engine battery (at the steel frame between the seats) is not removed, a new weight and balance report is not necessary. After the inspection and overhaul of the propeller hub is done, the propeller must be reinstalled.
Note: This AD differs from the MCAI and/or service information as follows:
(1) The MCAI did not have a required action if cracks were found during the inspection. This AD requires the propeller hub to be overhauled by the manufacturer before further flight if cracks are found.
(2) The MCAI allowed continued flight over the 15 hour propeller TIS limit (up to the annual inspection) if the propeller TIS was less than 15 hours as of the effective date of this AD. For propellers at or less than 15 hours TIS, the FAA is requiring the propeller hub to be overhauled by the manufacturer upon the accumulation of 15 hours TIS or prior to further flight if cracks are found, whichever occurs first.
(3) The service information allows for the pilot to perform the inspection and the removal and reinstallation of the propeller. By FAA regulation (14 CFR part 43), the pilot is not allowed to do these actions and an appropriately-rated mechanic must perform these actions.
(4) The MCAI incorporates the service information. We have modified the procedures in the service information as stated above and incorporated the procedures into this AD. This AD only references the service information.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
