The FAA issued four airworthiness directives—all effective Dec. 26. Here they are:
1. Operators of Airbus A318, A319, certain A320s and A321 series aircraft must inspect retraction actuators on the main landing gear and replace certain ones due to reports of circumferential cracks. A cracked actuator could cause the main gear to collapse during landing or takeoff. This AD (2014-23-05) should impact 851 US-registered aircraft and if the main landing gear actuator needs new parts, the cost is estimated at $36,845 per actuator. FYI, EASA issued a similar AD on Dec. 11, 2013.
2. Due to reports of dual pitch rate sensor failures on certain Boeing 777s, FAA AD 2014-23-04 requires operators to inspect the four sensors and replace them if necessary. Failure of the sensor could cause the autopilot to disengagement automatically. FAA says only 47 US-registered aircraft are affected.
3. Concerns about improperly installed brake hydraulic lines prompted FAA to issue AD 2014-23-06 for certain Bombardier CL-600-2B19 (Regional Jet series 100 & 440) aircraft. The AD, based on reports of inboard and outboard hydraulic lines connected to the wrong ports on the main landing gear, requires installing a brack on the right and left lower aft-wing planks of the main landing gear. This follows a Transport Canada directive dated Feb. 12, 2014. This AD affects 526 US-registered aircraft and should cost $885 per aircraft.
4. To prevent a potential failure of the second-stage HPT air seal, which could cause an uncontained engine failure, FAA issued AD 2014-23-01 for Pratt & Whitney PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090 and PW4090-3 engines. This AD, which supersedes AD 2013-15-09, expands the original to include more parts numbers, removal of mating hardware if the second-stage HPT air seal is cracked, and a terminating action. The new AD impacts 116 engines on US-registered aircraft and parts alone should cost $698,920 per engine.