On 15 October 2013, the pilot of a Robinson R44 helicopter, registered VH-TZE, was conducting gravity survey work, north of Daly Waters, Northern Territory. On board were the pilot and a geophysical field technician. The survey consisted of landing about every 4 km along a planned grid to collect data.
At about 1630 Central Standard Time (CST), the pilot conducted a routine landing at a designated grid point. The technician disembarked with his equipment to carry out a reading, about 5 m away from the helicopter.
A short time later, the pilot saw the technician waving his arms in an attempt to gain his attention. The pilot looked toward the rear of the helicopter and saw a fire underneath, which was spreading into the engine bay. The pilot exited the helicopter and notified the landholders via phone so they could construct fire breaks to contain the ensuing grass fire. The occupants were uninjured; however, the helicopter was destroyed by the fire.
The Australian Transport Safety Bureau (ATSB) has been notified of 13 occurrences since 2000 where a helicopter has been destroyed by grass fire, with many reports highlighting the speed with which the grass ignited and the fire spread beyond control.
Robinson R22 and R44 helicopters have exhaust systems that are low to the ground. The Pilot Operating Handbook for both types has a note in Section 10, Safety Tips stating:
‘Do not land in tall dry grass. The exhaust is low to the ground and very hot; a grass fire may be ignited.’
Pre-flight briefings highlighting the dangers of landing on grass, especially in areas of high temperatures and low humidity, can reinforce the importance of carefully choosing a landing site.