AC 120-42B ETOPS and Polar Ops - Code7700

AC 120-42B 6/13/08of each airplane’s APU in-flight starting capabilities. Specifically, the certificate holder mustensure that each airplane’s APU periodically is sampled rather than repeatedly sampling thesame APUs. The certificate holder may adjust sampling intervals according to systemperformance and fleet maturity. The certificate holder and its CHDO should periodically reviewthe certificate holder’s APU in-flight start program data to ensure that the in-flight startreliability is maintained. Should the rolling 12-month APU in-flight start rate drop below95 percent, the certificate holder should initiate an investigation into any common cause effectsor systemic errors in procedures.(2) The certificate holder should include the criteria below in their APU in-flight startprogram. The certificate holder should make APU in-flight starts subject to the followingconditions:(a) In-flight APU starts do not need to be performed on ETOPS flights; however,the APU must be in the ETOPS configuration in accordance with the appropriate CMPdocument, if applicable, for credit to be allowed.(b) If in-flight APU start is performed on an ETOPS flight, the start may beattempted on the return leg.(c) The start attempt should be initiated before top of descent, or at such time thatwill ensure a 2-hour cold soak at altitude before the start attempt.(d) Within route or track constraints, the objective would be met by attempting astart near the highest altitude assigned the route or track, and the final attempt near the loweraltitude limits of the route or track, as defined by ATC. These altitudes should be representativeof the ETOPS routes flown.(e) If the APU fails to start on the first attempt, subsequent start attempts may bemade within the limits of the airframe and APU manufacturer’s recommended procedures.(3) The certificate holder must report any operationally required APU in-flight startfailures occurring during actual ETOPS operations to its CHDO within 96 hours. The certificateholder also must report any occurrences of an ETOPS configured APU in-flight unsuccessfulstart attempt occurring during routine sampling (which exceed the airframe and APUmanufacturer design specifications) to its CHDO. The final report should include correctiveactions taken as well as the status of corrective action programs and fleet upgrades.n. Configuration Maintenance and Procedures (CMP).(1) The CMP Standard specifies any additional configuration, maintenance oroperational requirement that is uniquely applicable to ETOPS. The requirements in the CMP areestablished by the FAA at the time of initial ETOPS type design approval of the airplane-enginecombination. The CMP document typically is published and maintained by the airplanemanufacturer and includes identified CMP requirements. Airplane manufacturers may continueto release CMP revisions beyond the basic revision level required for ETOPS. The CMP revisionlevels required for specific airplane-engine combinations are typically listed in the front of theCMP or may be controlled through issuance of customized CMP documents. The certificatePage 22 Par 301