Airworthiness Directive · Amendment 39-16847 · Eurocopter France Model AS350B, B1, B2, B3, BA, C, D, and D1; and AS355E, F, F1, F2, N, and NP Helicopters
Eurocopter France Model AS350B, B1, B2, B3, BA, C, D, and D1; and AS355E, F, F1, F2, N, and NP Helicopters
Superseded. A later AD replaced this one: AD 2011-22-05 R1. Comply with the one in force.
Eurocopter Model AS350B, B1, B2, B3, BA, C, D, D1; and Model AS355E, F, F1, F2, N, and NP helicopters; with tail rotor (T/R) pitch control rod (control rod), part number (P/N) 350A33-2100-00, -01, -02, -03, -04; P/N 350A33-2121-00, -01, -02; P/N 350A33-2143-00; or P/N 350A33-2145-00 or -01, installed; certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) for the Eurocopter France (Eurocopter) Model AS350B, B1, B2, B3, BA, C, D, and D1 helicopters; and Model AS355E, F, F1, F2, and N helicopters with certain tail rotor pitch control rods installed. That AD requires a daily check of the tail rotor (T/R) pitch control rod (control rod) outboard spherical bearing (bearing) for play. If play exists, that AD requires measuring the bearing's radial and axial play. Since that AD was issued, an incident occurred where the pilot of a Model AS350 helicopter felt vibrations in the anti-torque pedal in flight, resulting in a precautionary landing. An investigation determined that the control rod showed extensive wear on the ball- joint. This superseding AD maintains the requirements of the existing AD, and expands the applicability to include the Model AS355NP helicopter and additional part-numbered control rods. The actions specified by this AD are intended to prevent failure of a control rod, loss of T/R control, and subsequent loss of control of the helicopter.
To prevent failure of a T/R control rod, loss of T/R control, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before the first flight of each day, place the T/R pedals in the neutral position. If the helicopter is fitted with a T/R load compensator, discharge the accumulator as described in the rotorcraft flight manual. Check the control rod bearing (bearing) for play on the helicopter, by observation and feel, by slightly moving the T/R blade in the flapping axis while monitoring the bearing for movement. See the following Figure 1 of this AD. The actions required by this paragraph may be performed by the owner/operator (pilot) holding at least a private pilot certificate, and must be entered into the helicopter maintenance records showing compliance with this AD in accordance with 14 CFR 43.9(a)(1)-(4) and 14 CFR 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.173, 121.380, or 135.439.
(b) If the Teflon cloth is coming out of its normal position within the bearing, totally or partially, or if there is discoloration or scoring on the bearing, before further flight, replace the control rod with an airworthy control rod.
(c) If a pilot or mechanic detects play, a mechanic must remove the control rod from the helicopter, and using a dial indicator, measure the bearing wear according to the following and as shown in Figures 2 and 3 of this AD:
(1) Remove the control rod from the helicopter.
(2) Mount the control rod in a vise as shown in Figure 2 of this AD.
(3) Using a dial indicator, take axial play readings by moving the spherical bearing in the direction F (up and down) as shown in Figure 2 of this AD.
(4) Install a bolt through the bearing and secure it with a washer and nut to provide a clamping surface when the bearing is clamped in a vise.
(5) Mount the control rod and bearing in a vise as shown in Figure 3 of this AD.
(6) Using a dial indicator, take radial play measurements by moving the control rod in the direction F as shown in Figure 3 of this AD.
(7) Record the hours of operation on each control rod.
(8) If the radial play exceeds 0.008 inch or axial play exceeds 0.016 inch, replace the control rod with an airworthy control rod before further flight.
(9) If the radial and axial play are within limits, reinstall the control rod.
(10) Thereafter, at intervals not to exceed 30 hours time-in-service, remove the control rod and measure the bearing play with a dial indicator in accordance with paragraph (c) of this AD.
(d) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Safety Management Group, DOT/FAA, ATTN: Jim Grigg, Manager, Rotorcraft Directorate, 2601 Meacham Blvd., Fort Worth, TX 76137, telephone (817) 222-5126, fax (817) 222-5961, for information about previously approved alternative methods of compliance.
(e) The Joint Aircraft System/Component Code is 6720: Tail rotor control system.
