FAA 

Aviation Safety 

DATE: October 28, 2015 

AD #: 2015-22-52 

EMERGENCY 

AIRWORTHINESS DIRECTIVE 

www.faa.gov/aircraft/safety/alerts/ 

This Emergency Airworthiness Directive (AD) 2015-22-52 is being sent to owners and 

operators of Airbus Helicopters Model AS350B3 helicopters. 

Background 

This Emergency AD was prompted by two acci Helicopters 

Model AS350B3 helicopters with a dual hydraulic investigations, 

loss of tail rotor (T/R) control during experienced a 

counterclockwise rotational yaw · anti-torque 

pedals felt jammed or events. The 

conditions in the control caused by 

a lack of pressure T/R hydraulic assistance 

with the switch on the yaw load compensator remains 

discharged and which significantly increases the pilot TIR control 

load and prevents . This Emergency AD prohibits performing the yaw 

load compensator switch) during preflight procedures and instead requires 

performing it procedures. This emergency AD also requires the yaw servo 

hydraulic switch switch) to be in the "ON" (forward) position before taking-off. The 

actions in this Emergency AD are intended to prevent takeoff without hydraulic pressure in the T/R 

hydraulic system, loss ofTIR flight control, and subsequent loss of control of the helicopter. 

Based on the accidents and incident, the European Aviation Safety Agency (EASA), which is 

the Technical Agent for the Member States of the European Union, issued EASA AD No. 2015-0178, 

dated August 26, 2015, to correct an unsafe condition for Airbus Helicopters Model AS 350 B3 

helicopters, equipped with a dual hydraulic system identified as modification OP 3082 or OP 3346. 

EASA advises of a perceived loss of TIR control that mimics jamming during take-off if the T /R 

hydraulic preflight checks are not performed in accordance with the checklist in the Rotorcraft Flight 

Manual (RFM). According to EASA, performing the T/R hydraulic preflight checks improperly may 

result in reduced function of the TIR hydraulic system, thereby significantly increasing the T/R 

control load for the pilot. 

FAA's Determination 

This helicopter has been approved by the aviation authority of France and is approved fot 

operation in the United States. Pursuant to our bilateral agreement with France, EASA, its technical 

representative, has notified us of the unsafe condition described in the EASA AD. We are issuing this 

emergency AD because we evaluated all information provided by EASA and determined the unsafe 

condition exists and is likely to exist or develop on other helicopters of the same type design. 

Related Service Information 

Airbus Helicopters issued Service Bulletin No. AS350-67.00.66, Revision 1, dated October 

22, 2015 (SB AS350-67.00.66), which specifies inserting specific pages ofthe bulletin into the RFM. 

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These pages revise the preflight and post-flight hydraulic checks by moving the T/R yaw load 

compensator check from preflight to post-flight. These pages also revise terminology within the flight 

manuals for the different engine configurations. 

Airbus Helicopters also issued Safety Information Notice No. 2944-S-29, Revision 0, dated 

August 26, 2015 (SIN 2944-S-29), which warns that attempting to take offwithout T/R hydraulic 

assistance (the yaw servo hydraulic switch on the collective grip in the "OFF" (aft) position) might be 

incorrectly perceived as T/R control failure (jam), which could lead to loss of control of the 

helicopter if not quickly identified and corrected. SIN 2944-S-29 also advises of the RFM update that 

revises the run-up hydraulic check starting procedures to no longer specify the yaw servo 

hydraulic switch. Pressing the yaw servo hydraulic switch, which is part load compensator 

check, discharges the yaw load compensator. The yaw load moved from 

preflight to post-flight procedures. Further, SIN L'JLJ·LJ.-~•-L.~ 

which is located on the collective grip, is also called 

off switch in various RFMs. 

yaw servo 

switch. 

performing the yaw load 

and instead performing the yaw 

This Emergency AD also requires the yaw 

be in the "ON" (forward) position before taking off. The 

be called the hydraulic pressure switch or hydraulic cut off 

Differences Between This Emergency AD and the EASA AD 

The EASA AD requires revising the RFM by incorporating procedures contained in Airbus 

Helicopters Service Bulletin No. AS350-67.00.66, Revision 0, dated August 26, 2015, and informing 

all flight crew of the RFM changes. This Emergency AD prohibits performing the yaw load 

compensator check during preflight procedures and requires it to be performed during post-flight 

procedures. This Emergency AD also requires the yaw servo hydraulic switch (collective switch) to 

be in the "ON" (forward) position before taking off. 

Interim Action 

We consider this Emergency AD to be an interim action. The design approval holder is 

currently developing a terminating action that will address the unsafe condition identified in this 

Emergency AD. Once this terminating action is developed, approved, and available, we might 

consider additional rulemaking. 

Authority for this Rulemaking 

Title 49 ofthe United States Code specifies the FAA's authority to issue rules on aviation 

safety. Subtitle I, Section 106, describes the authority ofthe FAA Administrator. "Subtitle VII, 

Aviation Programs," describes in more detail the scope ofthe Agency's authority. 

We are issuing this rulemaking under the authority described in "Subtitle VII, Part A, 

Subpart III, Section 44 701, General requirements." Under that section, Congress charges the FAA 

with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, 

methods, and procedures the Administrator finds necessary for safety in air commerce. This 

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regulation is within the scope of that authority because it addresses an unsafe condition that is likely 

to exist or develop on products identified in this rulemaking action. 

Adoption of the Emergency Airworthiness Directive (AD) 

We are issuing this Emergency AD under 49 U.S.C. Sections 106(g), 40113, and 44701 

according to the authority delegated to me by the Administrator. 

2015-22-52 Airbus Helicopters: Directorate Identifier 2015-SW-074-AD. 

(a) Applicability 

This Emergency AD applies to Airbus Helicopters Model AS350B3 hel"""''"i-"'""" with a dual 

hydraulic system installed, certificated in any category. 

Note 1 to paragraph (a) of this Emergency AD: 

AS350B3 helicopters is referred to as Airbus ... v •• .uu• 

(b) Unsafe Condition 

(d) Compliance 

pressure in a tail rotor 

control and subsequent loss 

You are responsible for performing each action required by this Emergency AD within the 

specified compliance time unless it has already been accomplished prior to that time. 

(e) Required Actions 

Before further flight, stop performing the yaw load compensator check (collective switch) 

during preflight procedures, and instead perform the yaw load compensator check during post-flight 

procedures. The yaw servo hydraulic switch (collective switch) must be in the "ON" (forward) 

position before takeoff. 

Note 2 to paragraph (e) ofthis Emergency AD: The yaw servo hydraulic switch is also called 

the hydraulic pressure switch or hydraulic cut off switch in various Airbus Helicopters flight 

manuals. 

(f) Special Flight Permit 

A special flight permit is prohibited. 

(g) Alternative Methods of Compliance (AMOCs) 

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this 

Emergency AD. Send your proposal to: Stephen Barbini, Flight Test Engineer, Regulations and 

Policy Group, Rotorcraft Directorate, FAA, 10101 Hillwood Pkwy, Fort Worth, TX 76177; telephone 

(817) 222-5110; email 9-ASW-FTW-AMOC-Requests@faa.gov. 

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(2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR 

part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal 

inspector, the manager of the local flight standards district office or certificate holding district office, 

before operating any aircraft complying with this Emergency AD through an AMOC. 

(h) Additional Information 

(1) For further information contact: Stephen Barbini, Flight Test Engineer, Regulations and 

Policy Group, Rotorcraft Directorate, FAA, 10101 Hillwood Pkwy, Fort Worth, TX 76177; telephone 

(817) 222-511 0; email stephen.barbini@faa.gov. 

(2) Airbus Helicopters Service Bulletin No. AS350-67.00. 

2015, and Airbus Helicopters Safety Information Notice N 

26, 2015, provide additional information about this 

information referenced in this AD, contact: 

TX 75052; telephone (972) 641-0000 

http://www · 

Issued in Fort Worth, Texas, on October 28, 2015. 

LanceT. Gant, 

Manager, Rotorcraft Directorate, 

Aircraft Certification Service. 

4 

October 22, 

dated August 

service 

Grand Prairie,