Technical and Safety Representative, Captain Phil Stevens discusses the current problems with drone regulations in regards to helicopter safety.

Whilst a drone can enter the engine of a large commercial jet, and will no doubt cause an engine failure and possible fire, the crew can hopefully deal with the fire and successfully land on the remaining engine or engines. However, the risk to helicopters is even greater because many helicopters operate at a low level and CASA currently allow drones to fly up to 400 feet.


There are two main operations in which helicopters operate at low level. One is surf rescue. The main function of the crew is to find the survivor in the surf, so they will not be looking for drones. The second is Emergency Medical Services helicopters. Their main concern on landing at a crash site is wires, because they know that police, ambulance and fire personnel do not always set up the landing site free from wires. Therefore they will not be looking for drones.

A typical scenario could be an emergency situation where a drone operator decides to fly overhead to obtain video footage to sell to a TV network. Even if limited to CASA’s 400 feet, the drone will still present a serious hazard to a rescue helicopter coming in to land or a searching the surf. The crew will be intently looking for wires or the survivor, so may well not see the drone at all. If it hits the tail rotor the helicopter will crash, probably into the emergency scene below. There will almost certainly be fatalities.

Other possible problems for helicopters that now cruise at 140 knots are if the drone comes through the windscreen the crew may be injured and the helicopter will crash. The drone may also hit the main rotor or flying controls to the main rotor, jamming them and again resulting in a crash.

Should the tail rotor of a helicopter fail, the fuselage will rotate in the opposite direction to the rotation of the main rotor because of the torque being applied. The only way to stop this out of control rotation of the fuselage is to remove all power from the main rotor.

With all power removed the helicopter fuselage will stop rotating but the helicopter is now in autorotation with rates of descent between 2,000 and 4,000 feet per minute. The pilot will require a large flat area to land safely. If this is not available the helicopter will crash. In my experience perhaps only about 50% of helicopter pilots will successfully land without a tail rotor.

The CASA proposed weight restriction above which drones will need to be regulated is 2.0 kg. At this weight the tail rotor will absolutely be destroyed if hit by a drone.

In fact, even a 250 gram or 500 gram drone will probably destroy the tail rotor as they typically rotate at 1500 to 2,000 RPM. The 2.0 Kg weight limit is far too high.

The top speed of a helicopter’s main rotor blade is around 550 miles per hour. Should the helicopter crash, bits of the composite material of the rotor blade will be flying in all directions at that speed, so the risk of serious injury or death for people on the ground is greater than for the crew. Should a drone cause a helicopter to crash the fatalities could be very high. The crew of a rescue helicopter is typically about 5. They may be ok but the rescue personnel on the ground will be at very high risk indeed, so there may be 10 or more fatalities.

For example, in 1968 a Bell 205 ferried 26 journalists to a Bass Strait oil rig. They were all dropped off and then the helicopter went up to get photographs. On arriving in the hover at the rig, the tail rotor failed and the helicopter spun and crashed on the deck. Those on board suffered minor injuries. Those below the deck level were all ok. The three standing on the steps and having some part of their body above the helideck level were all killed.

I am enclosing a link to a video on Youtube that demonstrates what can happen. Whilst it is dramatic, it does accurately portray the typical result of a drone hitting a tail rotor when there is no where for the pilot to make a safe, emergency landing.

Video: Drone hits air ambulance

Suppliers of Drones

I have been doing an unofficial survey of the many suppliers of drones in the shopping malls. This is what I have found:

  • Most do not supply the CASA regulations to the purchasers and do not even know there are regulations;
  • Many drones are being purchased as toys for children. Presumably these children will operate the drone unsupervised;
  • Some drones go out of range of the controller at about a kilometre. After that the drone is uncontrolled.

My question for CASA is, “Would you issue a pilot licence to an 8 to 10 year old child? No. So why will you allow a similar child to fly a drone?”

Possible Solutions

  1. Do not have a weight category under which drones do not need to be regulated.
  2. All drones should be supplied with a copy of CASA’s regulations.
  3. All operators should be licenced and trained to operate a drone.
  4. All drones should have the operator’s name, address and licence details engraved on the drone or the serial number recorded so that the owner can be traced in the event of an accident. This will also enhance the operator’s tendency to abide by the regulations.
  5. Any time an aircraft or helicopter is seen the drone should be landed immediately until the aircraft/helicopter is clear of the area.

Phil Stevens is a retired 50-year professional helicopter pilot. He is currently a Safety and Technical representative for the AFAP, AIPA and AusALPA for RPA’s, helicopters, HUPER and ADO.

His initial training training was with the RAAF on the Winjeel and then the Australian army on Bell 47 helicopters. During his career, he has been a Chief Pilot, a CFI, a Deputy Chief Pilot and Head of Training in Abu Dhabi Helicopters (75 pilots flying 35,000 hours a year), Operations Manager of Abu Dhabi Aviation, a VVIP pilot in Royal Flight Oman and Line Training Captain in Bristow Australia. He is am also a certified CRM Facilitator.

This article was originally published in Air Pilot E1 2017


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