This is a text on the Australian CASA website
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Light helicopters continue to be damaged or destroyed in fly-away accidents after they have been left unattended. Their pilots should have read the aircraft flight manuals.
It happens for many reasons: to open a gate for stock, to refuel, to speak with people on the ground, and in one case, a pilot’s urgent need for a ‘relief break’, as the ATSB called it, with characteristic tact. In all these cases, the result was a destroyed helicopter. Light helicopters, such as the Robinson R22 and R44 types that dominate the piston-engine helicopter market, are not safe when unattended, even with control locks.
‘What often happens is that the collective rises after a gust of wind or downwash from another helicopter, and the helicopter goes up’ CASA rotary wing flying operations inspector, David Threlfo, says.
In one case a pilot was killed by the main rotor blade, and in another a passenger was injured by walking into the tail rotor, both times with unattended helicopters.
There seems to be confusion among helicopter operators as to whether leaving a running helicopter unattended is legal or not. For pilots of Robinson R22, R44 and R66 helicopters it is illegal. The aircraft flight manuals (pilot’s operating handbooks) for the R22, R44 and R66 all say ‘never leave helicopter flight controls unattended while engine is running.’ They have said this since at least 2007.
As part of the aircraft flight manual (unless otherwise exempted) this directive trumps the other laws, regulations and orders governing helicopter flight in Australia.
‘Now that Robinson has decided to put that in, it changes the law, because Civil Aviation Regulation 138 says in effect that “you will comply with the manufacturer’s aircraft flight manual”,’ Threlfo says.
For pilots of other types of helicopters with aircraft flight manuals that do not forbid unattended ground running, there are two relevant laws. Civil Aviation Regulation 225, and Civil Aviation Order 95.7 paragraph 7.
CAR 225 (1988) says: ‘... the pilot in command must ensure that one pilot is at the controls of an aircraft from the time at which the engine or engines is or are started prior to the flight until the engine or engines are stopped at the termination of a flight’.
CAO 95.7, paragraph 7, is one of the many exemptions to the current civil aviation regulations. It sets out the conditions that must be met for a pilot of a single-pilot helicopter to leave the aircraft while it is running.
These are that:
The helicopter is fitted with skid-type landing gear.
The helicopter is fitted with a serviceable means of locking both the cyclic and collective controls. (A lock fitted only to the collective control is insufficient.)
A passenger in a control seat fitted with fully or partially functioning controls cannot interfere with the controls.
The pilot’s absence from the cockpit is essential to the safety of the helicopter or of someone on or in the vicinity of the helicopter.
The pilot remains in the immediate vicinity of the helicopter.
The message is clear: leaving a running helicopter unattended on the ground is dangerous, even with approved control locks fitted. That’s why pilots should only do it for a safety reason that’s stronger than the inherent danger. But not if they fly Robinson helicopters – for them it’s unambiguously illegal.
For a two-pilot helicopter, CAR 225 allows one pilot to leave the aircraft while it is still running, as long as the other pilot remains at the controls. However, for single-pilot operation the pilot can only leave the helicopter for the safety of the helicopter, or people on or near the helicopter.
Opening gates, hot refuelling, and talking with ground staff are not valid reasons to leave a running helicopter, Threlfo says. On the subject of ‘immediate vicinity’ he says: ‘If we’re talking 100 metres away to get a fuel drum, that’s not in the immediate vicinity’.
The legal situation is that CAO 95.7 paragraph 7 exempts only parts of CAR 225 and CAR 230. CAR 138, which says that the aircraft flight manual takes precedence, still applies, and if there is a conflict, overrules CAO 95.7.
Despite several accidents, including fatals, it's still a common practise in bush work, so I'm told!
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