AO-2014-002

On 5 May 2014 the pilot of a BK117 helicopter with four other people on board experienced a double engine power loss during a hospital patient transfer flight between Ashburton and Christchurch. The pilot made an emergency landing without power onto farmland near Springston, with no injuries sustained by the occupants and minor damage to the helicopter.

It was later determined that the double engine power loss had been caused by lack of fuel flow to the engines, despite there being a large quantity of fuel in the main fuel tanks. The cause of the lack of fuel flow to the engines was the pilot's incorrect management and configuration of the aircraft's fuel supply system, which prevented the fuel in the main tanks getting to the engines.

The pilot's lack of recent experience on the BK117 was a contributory factor in this event, including the absence of any recent training or competency assessment on the aircraft type. The pilot did not refer to a checklist when carrying out the normal pre-flight, before-start and after-start procedures. Had he referred to a checklist he would have likely corrected the error in the fuel system configuration before flight. The company that operated the helicopter did not have any procedures in place to address the lack of recent experience, such as additional training, supervision or a policy on the use of written checklists in such a situation.

A contributing factor to the power loss was the pilot's inability to detect the caution lights that would have alerted him to the incorrectly configured fuel system, due to the cockpit lighting dimmer switch being left on in daylight. A modification of the helicopter to enable the use of night vision equipment was found to have adversely affected the readability of the caution lights during daylight, when the cockpit lighting dimmer was on. A design feature of the BK117 fuel system meant that both engines lost power within seconds of each other.

The Commission made the following findings:
- both engines lost power due to fuel starvation, because the pilot did not switch on the fuel transfer pumps after starting the engines
- the pilot should not have operated the flight because he had not been assessed for his type-specific knowledge or checked for competency on the BK117 in the previous five years, and he lacked recent experience on the aircraft type
- the operator's system for maintaining oversight of its pilots' proficiency and currency was not robust enough to ensure that this pilot was proficient and sufficiently current to fly the BK117
- a cockpit lighting modification to the helicopter had adversely affected the readability of the caution lights during daylight, when the dimmer switch was on. Brightly illuminated caution lights should have alerted the pilot to the incorrectly configured fuel system and the low fuel levels in the supply tanks, and could have prevented the incident
- the helicopter was not designed to generate an aural warning of a critically low fuel level in the supply tanks. An aural warning, as fitted to later designs, would have alerted the pilot to the potential loss of engine power, and could have prevented the incident
- the operator did not require pilots to refer to written checklists if they lacked recent experience on an aircraft type. The pilot did not refer to a written checklist; had he done so he would have been prompted to: switch the fuel transfer pumps on, which would have prevented the fuel starvation; and turn the dimmer switch off, which should have ensured the caution lights were visible to the pilot.

The Commission made the following recommendations:
- on 25 February 2016 the Commission recommended to the Director of Civil Aviation that he review all modifications to the cockpit lighting on BK117 helicopters for night vision use, to ensure they do not unduly increase the risk of a similar incident occurring. If they do introduce an unacceptable level of risk, changes to the installation, such as alow-fuel-level aural warning or brighter LED (light-emitting diode) caution lights, should be required
- on 25 February 2016 the Commission recommended to the Chief Executive Officer of Garden City Helicopters Limited that he amend company policies, procedures and practices relating to the management of pilot competency. These amendments should include annual recurrent training and regular proficiency checks for all pilots on all aircraft types flown. For pilots who lack recent experience on an aircraft type, the amendments should introduce increased supervision, additional training, and the use of written checklists
- on 25 February 2016 the Commission gave notice to the Director of Civil Aviation that the Commission had recommended to the Chief Executive Officer of Garden City Helicopters that he amend company policies, procedures and practices relating to the management of pilot competency

The key lessons identified from the inquiry into this occurrence were:
- pilots who lack recent experience on an aircraft type should refer to written cockpit checklists when carrying out normal and emergency procedures
- pilots who fly multiple aircraft types concurrently must remain vigilant to inadvertently transferring habits and procedures from one type to another
- operators who require their pilots to fly different aircraft types must have robust policies and procedures that ensure the pilots are appropriately experienced, trained and current on each aircraft type.