EC55, en-route, Hong Kong China, 2003

EC55, en-route, Hong Kong China, 2003


On 26 August 2003, at night, a Eurocopter EC155, operated by Hong Kong Government Flight Service (GFS), performing a casualty evacuation mission (casevac), impacted the elevated terrain in Tung Chung Gap near Hong Kong International airport.

Event Details
Event Type
Flight Conditions
Flight Details
Type of Flight
Take-off Commenced
Flight Airborne
Flight Completed
Phase of Flight
Tung Chung Gap near VHHH
Into terrain, No Visual Reference, Vertical navigation error, VFR flight plan
Flight / Cabin Crew Co-operation, Procedural non compliance, Spatial Disorientation, Violation
Damage or injury
Aircraft damage
Hull loss
Non-aircraft damage
Non-occupant Casualties
Occupant Fatalities
Most or all occupants
Number of Occupant Fatalities
Off Airport Landing
Causal Factor Group(s)
Aircraft Operation
Safety Recommendation(s)
Aircraft Operation
Aircraft Airworthiness
Investigation Type


On 26 August 2003, at night, a Eurocopter EC155, operated by Hong Kong Government Flying Service (GFS), performing a casualty evacuation mission (casevac), impacted the elevated terrain in Tung Chung Gap near Hong Kong International airport.


The following is an extract from the official accident Report published by the Accident Investigation Division of the Civil Aviation Department, Hong Kong:

“There was evidence to suggest that the pilot carried out a pre-flight briefing in the GFS flight planning room, but there was no evidence of any communication at that time or subsequently between the pilot and aircrewman that addressed the manner in which the flight was to be conducted. Both crewmembers proceeded independently to the helicopter and it was clear from the cockpit voice recorder (CVR) that at the time of manning the aircraft […] the pilot was not aware of the casevac destination.”

The flight plan was filed via Silvermine pass but the pilot decided to fly via Tung Chung Gap which, according to the Report, “was marginally more direct”.

“The weather forecast and Meteorological Aerodrome Report (METAR) at HKIA [Hong Kong Int’l Airport] were within GFS limits for single pilot flight at night over low-lying terrain and sea, but there was no precise information available concerning the weather conditions over Tung Chung Gap”.

After take off, the crew observed what seemed to be fair visibility conditions over Tung Chung Gap and proceeded according to the changed flight plan. Subsequently, in the gap the crew encountered low visibility conditions due to low cloud.

A comment recorded by the CVR [3 minutes after take off] indicated that the pilot was still in visual contact with the surface. However, ten seconds later the pilot remarked that the way ahead was “very marginal” but that he was still “visual”.

Following a short radio telephony exchange with ATC the crew were cleared to leave 1200 ft and climb 1500 ft. The pilot acknowledged the received instruction.

“However, the aircraft remained in level flight at 1,200 feet. [Twenty one seconds after the beginning of the communication exchange with ATC] the CVR and Flight Data Recorder (FDR) ceased recording. This timing coincided with first point of contact with the surface.”

The Cause and the contributory factors (“active and latent failures”) to the accident were given as:

  • “The pilot did not conduct a pre-flight briefing;
  • The pilot made an inappropriate decision to navigate via Tung Chung Gap at a low altitude and high cruise speed, at night, in marginal meteorological conditions;
  • The pilot suffered from an error perception (confirmation bias);
  • The pilot did not comply with GFS weather minima;
  • The pilot did not comply with GFS teaching and common practice for navigating via Tung Chung Pass and Gap at night;
  • The pilot was affected by mission pressure to achieve the GFS on-scene target times;
  • The crew accepted an unnecessary hazard;
  • A degree of complacency affected both crewmembers, created by the fact that they flew regularly together and that the accident flight was over a familiar route and was perceived by the crew as being routine in nature;
  • The pilot showed impaired reasoning power and decision-making capabilities. This may have been due to insufficient rest combined with circadian disruption;
  • Both crewmembers were affected by low levels of alertness and arousal;
  • The crew did not adhere to a number of the basics tenets of CRM;
  • The GFS Operations Manual did not include the absolute minimum en route height above the surface for night casevac operations.
  • The GFS did not have a documented system for the proactive identification of hazards and systematic management of risk in flight operations;
  • The discretion given to pilots, in relation to the level of risk associated with casevac missions carried out by the GFS, was not necessarily matched to the operational need.”

The Report's recommendations beginning on page 118, also focus on organisational and institutional issues (see Further Reading).

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Further Reading

For further information see the full accident report published by Accident Investigation Division, Hong Kong.

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