Airworthiness Directive · Amendment 39-18035 · M/r system
Agusta S.p.A. Helicopters
Superseded. A later AD replaced this one: AD 2017-23-08. Comply with the one in force.
This AD applies to Agusta Model AB139 and AW139 helicopters with main rotor (M/R) rotating scissors part number (P/N) 3G6230A00733, with a lower half scissors spherical bearing (bearing) P/N 3G6230V00654 installed, certificated in any category.
We are superseding Airworthiness Directive (AD) 2014-07-51 for AgustaWestland S.p.A. Model AB139 and AW139 helicopters with certain main rotor (M/R) rotating scissors installed. AD 2014-07-51 required repetitively inspecting the M/R rotating scissors for play of the lower half scissor spherical bearing (bearing) and removing the bearing if there was play beyond allowable limits. AD 2014-07-51 also required removing all affected bearings. AD 2014-07-51 was prompted by reports of certain bearings dislodging from certain M/R rotating scissors. This new AD retains the requirements of AD 2014-07-51, expands the applicability, and requires installing a special nut. These actions are intended to detect excessive play of the bearing and prevent failure of the M/R rotating scissors and subsequent loss of control of the helicopter.
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) For helicopters with the M/R rotating controls installed without special nut P/N 3G6230A06851, within 5 hours time-in-service (TIS), and thereafter before the first flight of each day or at intervals not exceeding 24 hours, whichever occurs later; and for helicopters with the M/R rotating controls installed with special nut P/N 3G6230A06851, within 25 hours TIS, and thereafter at intervals not exceeding 25 hours TIS:
(i) Visually inspect the M/R rotating scissors for damage using a light source and a magnifying glass, paying particular attention to the bearings. Some examples of damage are shown in Figures 4 through 8 of AgustaWestland Bollettino Tecnico No. 139-392, dated September 23, 2014 (BT 139-392). If there is damage, before further flight, remove the bearing.
(ii) Inspect the M/R rotating scissors for play 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 play, before further flight, accomplish a detailed inspection of the M/R rotating scissors in accordance with steps 9.1 through 12.9 of AgustaWestland AW139 Document Code 39-C-62-31-00-00A-286C-A, Rotating control installation—Fixed swashplate and rotating scissors—Detailed inspection, issue 001, dated August 6, 2012. Any play beyond allowable limits requires removing the bearing before further flight.
(2) Within 50 hours TIS from August 20, 2014, remove any bearing from a M/R rotating scissors with serial numbers (S/N) listed in Table 1 of AgustaWestland Bolletino Tecnico No. 139-368, dated March 19, 2014 (BT 139-368), on which the bearing has never been replaced; or from a M/R rotating scissors on which the bearing was replaced with a bearing with a S/N listed in Table 2 of BT 139-368.
(3) Within 100 hours TIS, install special nut P/N 3G6230A06851 in accordance with steps 5.1. through 6., Part II, of the Compliance Instructions, of BT 139-392.
(4) Prior to installing a M/R rotating scissors with a S/N listed in Table 1 of BT 139-368, replace the bearing and re-identify the M/R rotating scissors in accordance with paragraphs 4.2 through 4.4., Part II, of the Compliance Instructions of BT 139-368.
(5) Do not install a bearing with a S/N listed in Table 2 of BT 139-368 into any M/R rotating scissors.
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.
Aircraft
