H2F Weekly Mayday #16

WEEK 16

H2F brings you the ‘helicopter mayday of the week’ with a short accident report summary. I tell you what happened. You think more about why it happened. We all learn from it. Because that’s what accident reporting is for.

TITLE

Main rotor strike during mountain rescue leads to tail strike and loss of control during emergency landing.

WHAT?

A Sécurité Civile EC145 was tasked to assist an injured hiker in mountainous terrain near the Col de la Taillandère in the French Pyrenees. After landing below the casualty and disembarking the mountain rescue team, the helicopter returned to recover the rescuers and victim. Concerned that deteriorating cloud conditions might prevent completion of the mission, the crew changed from a hoist recovery as they had planned, to a skid-support pickup intended to expedite the extraction. During the manoeuvre, the main rotor struck the slope above the aircraft, producing severe vibrations and making the control of the aircraft difficult.  

WHERE?

Laruns in the Pyrénées-Atlantiques region of France, at an altitude of over 6000ft during a mountain rescue operation.  

WHEN?

6 June 2020. The BEA-É report was published on 17 July 2021.  

HOW?

After the rescue team reported they were ready, the helicopter ran in and and the crew elected to perform a skid-support extraction rather than the originally intended hoist operation. While manoeuvring with one skid in contact with the slope, the main rotor blades struck scree above the rescue party. The pilot immediately abandoned the pickup and descended toward the previous landing area. While attempting to arrest the descent and reduce speed for landing, the tail boom, tail rotor, and vertical fins struck the ground. Damage to the tail rotor and rear transmission system resulted in loss of control, and the aircraft turned through 270 degrees during the forced landing.  

CONDITIONS?

The rescue was conducted in steep mountainous terrain under deteriorating weather conditions. The crew was aware that advancing cloud threatened completion of the mission and focused on extracting the entire rescue team and casualty before conditions worsened. But the skid-support technique required precise positioning, with less than 30cm clearance. The crew had limited recent practice in specific mountain techniques, and no formal procedural framework existed for conducting this type of skid-support recovery.  Although both crewmembers had extensive experience and had worked together at the same base since 2003, the hoist operator had slept only four hours the previous night.

OUTCOME?

The helicopter sustained severe damage to the rotor system, tail boom, and rear transmission. The pilot successfully landed the aircraft, and all crewmembers, rescuers, and the casualty escaped injury.  

WHY?

• Failure to adequately identify and assess the recovery point before commencing the pickup.
• Loss of shared situational awareness resulting from communication breakdowns between the crew and rescue team.
• Time pressure caused by rapidly deteriorating cloud conditions, leading the crew to prioritize speed of extraction.
• Late decision to switch from hoisting to skid-support recovery, reducing monitoring and guidance during the final phase.
• Very small clearance margins that provided little tolerance for error.
• Lack of recent practice in specialized mountain rescue techniques.
• Absence of formal procedures or a work framework for skid-support operations.
• Long-standing familiarity among team members that discouraged challenge and mutual monitoring.
• Fatigue affecting the hoist operator after limited sleep.
• Standard operating procedures providing inadequate defenses against fatigue.

REFERENCE?

Bureau d’Enquêtes et d’Analyses pour la sécurité de l’État (BEA-É). (2021, July 17). Accident involving Airbus Helicopters EC145 (BK117 C-2) F-ZBQF “Dragon 64” during a mountain rescue operation near Laruns, Pyrénées-Atlantiques, on 6 June 2020. BEA-É.

Note:

Accident reports selected from the following open source databases: US NTSB; UK AAIB; Flight Safety Foundation’s Aviation Safety Network; Australia’s ATSB. Ireland’s AAIU; Taiwan’s TTSB; France’s BEA; Spain’s CIAIAC. Germany’s BFU.