Airworthiness Directive · Amendment 39-21464 · Main rotor system
Leonardo S.p.a. (Type Certificate Previously Held by Agusta S.p.A.) Helicopters
This airworthiness directive (AD) applies to Leonardo S.p.a. Model AB139 and AW139 helicopters, certified in any category, with main rotor (M/R) rotating scissors with a lower half scissor spherical bearing (bearing) P/N 3G6230V00654 installed.
The FAA is superseding Airworthiness Directive (AD) 2017-23-08 for Agusta S.p.A. (now Leonardo S.p.a.) Model AB139 and AW139 helicopters. AD 2017-23-08 required repetitively inspecting the main rotor (M/R) rotating scissors, removing certain lower half scissor spherical bearings (bearings) from service, replacing the removed bearings with a new bearing, and installing a special nut. This new AD retains the requirements of AD 2017-23-08 and requires replacing each affected bearing with a certain part-numbered bearing. This AD was prompted by investigation results determining that a quality control issue may have affected the production of the affected bearings. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) Within 5 hours time-in-service (TIS) after December 11, 2017 (the effective date of AD 2017-23-08), and thereafter before the first flight of each day or at intervals not exceeding 24-clock hours, whichever occurs later:
(i) Using a magnifying glass and a flashlight, visually inspect each bearing for wear of the bearing liner. Some examples of wear are shown in Figures 4 through 8 of Leonardo Helicopters Alert Bollettino Tecnico No. 139-392, Revision A, dated February 14, 2017 (BT 139-392). If there is any wear of the liner, before further flight, replace the bearing with bearing P/N 3G6230V00655 and install special nut P/N 3G6230A06851. Replacing the bearing with bearing P/N 3G6230V00655 constitutes terminating action for the remaining actions of this AD for the bearing.
(ii) Inspect each bearing for movement. Refer to Figure 9 of BT 139-392. If the bearing moves freely out of its seat, before further flight, replace the rotating scissor attachment flange with flange P/N 3G6220A00633, replace the bearing with bearing P/N 3G6230V00655 and install special nut P/N 3G6230A06851. Replacing the bearing with bearing P/N 3G6230V00655 constitutes terminating action for the remaining actions of this AD for the bearing.
(iii) Inspect the M/R rotating scissors for play and wear of each bearing, paying particular attention to the bearing staking condition, by manually moving the lower half scissor along the axis of the spherical bearing. Refer to Figure 1 of BT 139-392. If there is any play or wear beyond allowable limits, before further flight, replace the bearing with bearing P/N 3G6230V00655 and install special nut P/N 3G6230A06851. Replacing the bearing with bearing P/N 3G6230V00655 constitutes terminating action for the remaining actions of this AD for the bearing.
(2) Within 100 hours TIS after the effective date of this AD, replace and torque each lower half scissor nut with special nut P/N 3G6230A06851 to the M/R rotating scissor in accordance with the Compliance Instructions, Part II, steps 5.1 through 5.9 of BT 139-392, except you are not required to discard parts.
(3) Within 100 hours TIS after the effective date of this AD, remove each bearing P/N 3G6230V00654 from service and replace with bearing P/N 3G230V00655.
(4) After December 11, 2017 (the effective date of AD 2017-23-08), do not install on any helicopter any M/R rotating scissors with a bearing P/N 3G6230V00654 installed.
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.
