WEEK 20
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
Loss of control during low-level surveillance flight exposes systemic organisational safety failures.
WHAT?
A Spanish Directorate-General for Traffic (DGT) Eurocopter AS355 departed Madrid Cuatro Vientos airport on a routine traffic surveillance mission with a pilot, an air surveillance operator and an invited passenger. After approximately 14 minutes of normal surveillance activity, the helicopter deviated from briefed surveillance task and flew through mountainous terrain at very low level. While climbing along the side of a valley at low speed, the helicopter entered an unanticipated yaw, rapidly lost control and impacted the hillside before rolling onto its side.
WHERE?
Robledo de Chavela, Madrid, Spain.
WHEN?
5 March 2023. Final report published 27 November 2024.
HOW?
After deviating from traffic monitoring, the helicopter spent several minutes flying low over the San Juan Reservoir before entering a valley where it progressively lost airspeed while climbing with a tailwind. Recorded data showed increasing vibration, repeated heading changes and unstable pitch, roll and yaw before the helicopter entered an unanticipated yaw. The pilot misidentified the event as vortex ring state and responded by increasing collective instead of applying sustained right pedal, aggravating the loss of control. The investigation found no evidence of mechanical malfunction or aircraft performance limitations.
CONDITIONS?
The flight took place in mountainous terrain with local wind effects that increased the tailwind within the valley. The helicopter remained within weight and performance limits, but was flown at very low altitude with minimal safety margins. The operation was conducted as a single-pilot surveillance mission without formal operational procedures governing low-level surveillance techniques. The pilot had returned to operational flying after a prolonged absence without structured re-induction or mission-specific operational training.
OUTCOME?
The helicopter was destroyed following impact and rollover. The pilot was uninjured, while the air surveillance operator and passenger sustained serious injuries.
WHY?
Investigators concluded that the accident resulted from the pilot’s failure to recognise and correctly recover from an unanticipated yaw while operating at low speed with a tailwind in mountainous terrain. The investigation identified extensive contributing and latent factors:
Toxicology reports detected cocaine and MDMA (ecstasy) in the pilot’s blood. Expert analysis estimated cocaine use approximately four hours before the accident and MDMA approximately 29 hours earlier, although the report did not identify drug impairment as a direct causal factor.
The pilot had a documented history of rule-breaking, “show-off” flying, anti-authoritarian attitudes, risk-taking, procedural shortcuts, previous serious safety occurrences, failure to wear required corrective lenses, and concealing personal issues during aeromedical examinations. These behaviours were known within the organisation but were not effectively addressed.
The operator’s safety culture, supervision, pilot oversight, and training systems failed to intervene despite repeated warning signs. The organisation lacked documented procedures for surveillance operations, provided inadequate pilot re-induction after prolonged absence from flying duties, and operated within a legal and organisational framework that failed to prevent unsafe behaviours from becoming normalised.
The pilot misdiagnosed the emergency as vortex ring state and applied incorrect recovery actions, increasing collective rather than arresting the yaw with right pedal
REFERENCE?
Comisión de Investigación de Accidentes e Incidentes de Aviación Civil. (2024). Technical Report A-002/2023: Accident involving Eurocopter Aerospatiale AS355N, registration EC-JMK, at kilometre 2.400 of the M-512 road, Robledo de Chavela (Madrid, Spain), on 5 March 2023. Ministry of Transport and Sustainable Mobility, Government of Spain.
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.
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