Airworthiness Directive · Amendment 39-19153 · Main hydraulic system
Airbus Helicopters
Superseded. A later AD replaced this one: AD 2018-01-12 R1. Comply with the one in force.
This AD applies to Model AS350B3 helicopters with a dual hydraulic system installed, certificated in any category.
Note 1 to paragraph (a) of this AD: The dual hydraulic system for Model AS350B3 helicopters is referred to as Airbus modification OP 3082 or OP 3346.
We are superseding Airworthiness Directive (AD) 2015-22-53 for Airbus Helicopters Model AS350B3 helicopters. AD 2015-22-53 required revising the rotorcraft flight manual (RFM) to perform the yaw load compensator check after rotor shut-down and to state that the yaw servo hydraulic switch must be in the "ON" position before taking off. Since we issued AD 2015-22-53, Airbus Helicopters developed a modification of the ACCU TST switch. This new AD retains the requirements of AD 2015-22-53 and requires modifying the yaw servo hydraulic switch (collective switch) and replacing the ACCU TST button. 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) Before further flight, insert a copy of this AD into the rotorcraft flight manual, Section 4 Normal Operating Procedures, or make pen and ink changes to the preflight and post-flight procedures as follows:
(i) Stop performing the yaw load compensator check (ACCU TST switch) during preflight procedures, and instead perform the yaw load compensator check during post-flight procedures after rotor shut-down.
(ii) The yaw servo hydraulic switch (collective switch) must be in the “ON” (forward) position before takeoff.
Note 2 to paragraph (f)(1)(ii) of this AD: The yaw servo hydraulic switch is also called the hydraulic pressure switch or hydraulic cut off switch in various Airbus Helicopters rotorcraft flight manuals.
(2) Within 350 hours time-in-service:
(i) Install a timer relay for the yaw servo hydraulic switch (collective switch) by following the Accomplishment Instructions, paragraph 3.B.2.b.1, 3.B.2.b.2, 3.B.2.b.3, 3.B.2.b.4, 3.B.2.b.5, or 3.B.2.b.6, as applicable to the configuration of your helicopter, of Airbus Helicopters Service Bulletin (SB) No. AS350-67.00.64, Revision 0, dated February 25, 2015 (AS350-67.00.64). If your helicopter has an automatic pilot system, also comply with paragraph 3.B.2.b.7 of AS350-67.00.64.
(ii) Install an indicator light on the caution and warning panel by following the Accomplishment Instructions, paragraph 3.B.2.c.1 or 3.B.2.c.2, as applicable to the configuration of your helicopter, of AS350-67.00.64.
(iii) For helicopters with a Geneva Aviation P122 or P132 electrical console installed, replace the ESN-11 HYD TEST (ACCU TST) switch with a monostable toggle switch part number MS24658-16F.
(iv) For helicopters without a Geneva Aviation P122 or P132 electrical console installed, replace the bistable ACCU TST button on the control panel with a monostable button as depicted in Figure 1 or Figure 3, as applicable to the configuration of your helicopter, of Airbus Helicopters SB No. AS350-67.00.65, Revision 0, dated August 25, 2016.
(3) After the effective date of this AD, do not install a bistable ACCU TST button on any helicopter.
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.
