99-02-51: Starter Shaft Seal

99-02-51 Allison Engine Company, Inc.: Amendment 39-11108: Docket 99-NE-01-AD. Applicability: Allison Engine Company, Inc. AE 3007A and AE 3007C series turbofan engines, installed on but not limited to Embraer EMB-145 and Cessna 750 series airplanes. Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To prevent an in-flight engine shutdown due to loss of engine oil from the starter shaft seal, accomplish the following: (a) Prior to further flight, all ground engine starts at engine oil temperatures below 32 deg. F (0 deg. C) are prohibited except as provided in paragraphs (a) (1) and (a) (2) of this AD. (1) For Allison Engine Company engine models AE 3007A, AE 3007A1, AE 3007A1/1, and AE 3007A1/2, if the engine oil temperature has dropped below 32 deg. F (0 deg. C) prior to flight, perform a high-power leak check on each engine (at least three minutes at takeoff power, reference Allison Engine Company AE 3007A series maintenance manual, section 72-00-00, page 505, subtask 72-00-00-790-002). No leaks above serviceable limits are permitted (0.21 quarts/hour, 200 cc/hour per Allison Engine Company AE 3007A, Fault Isolation Manual, section 79-37-00, page 212, allowable leakage). (2) ForAllison Engine Company engine model AE 3007C, if the engine oil temperature has dropped below 32 deg. F (0 deg. C) prior to flight, monitor the engine oil level using the following procedures: (i) Operate engine at maximum continuous power for 10 minutes. Monitor the engine oil level. (ii) If an oil level decrease of greater than 1.0 quarts occurs, maintenance is required before further flight. (b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Chicago Aircraft Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Chicago Aircraft Certification Office. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Chicago Aircraft Certification Office. (c) This amendment becomes effective April 20, 1999, to all persons except those persons to whom it was made immediately effective by telegraphic AD 99-02-51, issued January 8, 1999, which contained the requirements of this amendment.