European Aviation Safety Agency Issued Alert Over Leonardo AW139 Main Landing Gears.

• An EASA Emergency Airworthiness Directive (AD) highlights a potential unsafe condition of certain Leonardo AW139 helicopters.
• The unsafe condition is related to the Main Landing Gear eye end of the MLG shock absorber piston rod.
• With an effective date of 15 April 2024, the unsafe condition needs to be detected and corrected.

The European Aviation Safety Agency (EASA) has issued an emergency airworthiness directive relating to the Leonardo AW139 helicopter, earlier this month.

Following issuance of OEM Leonardo Emergency Alert Service Bulletin (EASB) 139-783, the EASA airworthiness directive was issued specifying certain part numbers of Main Landing Gear (MLG) of the helicopter model.

The EASA received reports of “occurrences of a broken eye end of the MLG shock absorber piston rod” of the AW139, which upon investigation determined that the cause was fatigue cracking.

Reason of issuing the Emergency Airworthiness Directive :

• As per EASA, Occurrences of a broken eye end of the MLG shock absorber piston rod were reported.
• Subsequent investigation determined that the cause was fatigue cracking.
• This condition, if not detected and corrected, could lead to structural failure of the main landing gear possibly resulting in damage to the helicopter and injury to occupants.
• To address this potential unsafe condition, Leonardo issued the EASB providing inspection and replacement instructions.
• For the reason described above, this AD requires repetitive Special Detailed Inspections (SDI) of each affected part using Ultrasonic Testing and, depending on findings, replacement.
• This AD is considered to be an interim action and further AD action may follow.

Emergency Airworthiness Directive described that the condition “could lead to structural failure of the main landing gear possibly resulting in damage to the helicopter and injury to occupants” if not detected and corrected.

The EASA said Leonardo issued the emergency alert to provide inspection and replacement instructions for the affected part based on the number of landings undertaken by AW139 aircraft.

The Directive has divided the helicopters in two groups for the action part, where the Group 1 helicopters are those that have an affected part installed. Group 2 helicopters are those that do not have an affected part installed.

As per the information provided in the Airworthiness Directive from the link above, if during any inspection as required by the AD, discrepancies, as identified in the EASB, are detected on an affected part, affected part to be replaced with a serviceable part before next flight, in accordance with the instructions of the EASB.

However, EASA has clarified through the Directive that the Replacement of an affected part with a serviceable part, as defined in the AD, on a helicopter does not constitute a terminating action(s) for the repetitive inspections as required by the AD for that helicopter.

Picture Courtesy : KJ