Collision with terrain involving a Robinson R44, VH-YYF, near Hughenden, Queensland, on 1 February 2015

What happened

On 1 February 2015, the pilot of a Robinson R44 helicopter, registered VH-YYF, prepared for a local flight at Warwombie Station, near Hughenden, Queensland. The pilot did not observe any abnormalities during the pre-flight inspection, with oil quantity within the normal range, about 80 L of fuel on board, and no water or other contaminants found during a fuel drain and check. The helicopter was loaded within the normal operating weight and balance limitations. The temperature was 20 °C, the sky clear of cloud and the wind was calm.

At about 0800 Eastern Standard Time (EST), the helicopter lifted off normally. At about 20 ft above ground level, the pilot lowered the nose of the helicopter in attempt to gain forward speed and transition from hover to forward flight. The helicopter then sank quickly and the rotor rpm decayed. The pilot pulled back on the cyclic^[1] control in an attempt to flare and reduce the rate of descent, prior to contacting the ground. The left skid contacted the ground first and then the helicopter spun to the right. The rear of the right skid dug into the ground and the helicopter rolled onto the right side. The pilot selected the master switch off before exiting the helicopter uninjured. The helicopter sustained substantial damage (Figure 1).

Pilot comments

The pilot had about 9,000 hours total helicopter aeronautical experience. He had practiced autorotations often and believed that his experience enabled him to escape uninjured. The incident had happened very quickly and he was unsure what had caused the helicopter to sink and lose rotor rpm.

Figure 1: Damage to VH-YYF

Source: Daniel Cook

Safety message

The Robinson Helicopter Company Safety Notice SN-24 stated that rotor stall due to low RPM causes a very high percentage of helicopter accidents. These mostly occur close to the ground during take-off and landing. Safety Notice SN-10 reminds pilots to have their ‘reflexes conditioned so they will instantly add throttle and lower collective to maintain RPM in any emergency’.

The pilot in this incident had completed significant number of practice autorotations. The avoidance of injury highlights the benefits of practice. The following links provide information regarding practice autorotations:

• www.ainonline.com/aviation-news/hai-convention-news/2012-02-13/instructor-pilots-give-guidance-autorotation-training

• www.ainonline.com/aviation-news/aviation-international-news/2013-05-01/astar-accident-shines-light-autorotation-training

• www.aviationtoday.com/rw/training/specialty/Flight-Training-Tips-Dancing-With-the-Devil_13632.html

• www.faa.gov/documentLibrary/media/Advisory_Circular/AC_61-140.pdf

• www.faasafety.gov/files/gslac/library/documents/2011/Aug/56414/FAA%20P-8740-71%20Planning%20Autorotations%20[hi-res]%20branded.pdf

Aviation Short Investigations Bulletin - Issue 40

About this report Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, a limited-scope, fact-gathering investigation was conducted in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions. Publishing information  Released in accordance with section 25 of the Transport Safety Investigation Act 2003 Published by: Australian Transport Safety Bureau © Commonwealth of Australia 2015 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this report publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form licence agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you wish to use their material, you will need to contact them directly.

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1. A primary helicopter flight control that is similar to an aircraft control column. Cyclic input tilts the main rotor disc varying the attitude of the helicopter and hence the lateral direction.