Airworthiness Directive · Amendment 39-17327 · Engine Alliance Turbofan Engines
Engine Alliance Turbofan Engines
Superseded. A later AD replaced this one: AD 2016-22-11. Comply with the one in force.
This AD applies to all Engine Alliance GP7270 and GP7277 turbofan engines with a high-pressure turbine (HPT) stage 2 nozzle, part number (P/N) 2101M24G01, 2101M24G02, or 2101M24G03, installed.
We are adopting a new airworthiness directive (AD) for all Engine Alliance GP7270 and GP7277 turbofan engines. This AD requires initial and repetitive borescope inspections and removal from service before further flight if one or more burn holes are detected, in certain high-pressure turbine (HPT) stage 2 nozzles. This AD also requires mandatory removal from service of these HPT stage 2 nozzles at the next engine shop visit. This AD was prompted by a report received of inadequate cooling of the HPT stage 2 nozzle, leading to damage to the HPT stage 2 nozzle, burn-through of the turbine case, and engine shutdown. We are issuing this AD to prevent HPT stage 2 nozzle failure, leading to uncontrolled fire, engine shutdown, and damage to the airplane.
(1) Initially borescope inspect (360 degrees) the HPT stage 2 nozzle at the following:
(i) Before accumulating 1,500 cycles-since-new (CSN), if the nozzle has fewer than 1,450 CSN on the effective date of this AD.
(ii) Within the next 50 cycles, if the nozzle has 1,450 or more CSN on the effective date of this AD.
(2) Thereafter, repetitively borescope inspect (360 degrees) the HPT stage 2 nozzle within every 100 additional cycles-in-service.
(3) If during any inspection required by this AD, any burn holes are detected through the surface of the nozzle, remove the nozzle from service before further flight.
At the next engine shop visit, remove HPT stage 2 nozzles P/N 2101M24G01, 2101M24G02, and 2101M24G03 from service.
For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges except that the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit.
