A helicopter operating a medical service crashed in Malaysia, killing all five people on board. The aircraft is understood to have been on a mission at the time.

Authorities have secured the site and recovered wreckage to begin an investigation, with weather conditions and maintenance records the first items to be checked.

The conditions of air medical work

Medical transport helicopters link areas with poor hospital access, including islands, to care. The nature of the work means requests come in even when conditions are poor.

Countries therefore set separate criteria for launching and explicitly give pilots the authority to decline, an arrangement designed to separate judgements about urgency from judgements about safety.

The investigation and after

Helicopter investigations, unlike those into fixed-wing aircraft, must also examine mechanical factors specific to rotorcraft, with the main rotor system and gearbox components the central concerns.

Relevant agencies said maintenance records for the same type would be reviewed as well, and flight procedures could be adjusted depending on the findings.

Medical staff were reportedly among those killed. The organisations involved are conducting memorial and family support procedures.