Wire Strike Avoidance

Photo showing wires going to a shed

Wires running to a farm building.
How many wires can you see?

Since 1979, New Zealand helicopter pilots have had 116 wire strikes, resulting in 28 deaths, as at November 2015. Many of them were with power or phone cables, but 62 of them were from other wires, including fences and elevated gully wiring.

Any aircraft flying below 500 ft is at risk of a wire strike, but helicopters are especially susceptible due to the nature of the work they do.

Wire strikes are preventable, but only with a well-planned safety programme to identify hazards and put mitigations in place.

For Pilots

Most wire strikes occur in fine weather when there’s good visibility and the pilots often knew they were there. So there’s more than keeping a good lookout involved.

Important things to think about include:

  • Wires are thin and often nearly impossible to see until it’s too late.
  • Your workload, vision limitations, and a small lapse in concentration can lead to a fatal mistake.
  • The number of flying hours you have doesn’t lower your chance of a wire strike.
  • On-going training on wire strikes is essential.

The CAA recommends that all pilots be trained in wire strike avoidance.

Planning with Your Clients

Insist that your clients provide a detailed map showing wires, high fences, and other hazards, and get as much detail as possible. Stress that hazards in the surrounding areas must also be identified. In an emergency, you may need to fly outside the intended operating area.

Your hazard map needs to be comprehensive. You should also talk to neighbouring landowners or other operators who have experience working in the area.

Don’t just rely on the information the client provides. You should do a full reconnaissance of the area you are about to operate in from both the air and the ground, taking note of any structures that use power. Watch for any poles as they may have wires connected that you can’t see.

Also watch for single wires strung between farm buildings. They are particularly hard to see, and can also be attached to hidden structures.

Streams, gullies, and rivers all potentially have wires strung across them.

Health and Safety Duties


If you contract a pilot or aviation company, you will have duties under the Health and Safety at Work Act 2015. These duties will be around operating as a PCBU, being an officer, and working with other PCBUs. For more information, see the CAA Health and Safety web site, Part 137 Agricultural Operations.

 Specific information on duties of PCBUs can be found in the fact sheets:

Reducing Wire Hazards

Wherever possible, you must manage risks to ensure the farm is safe for aerial operations. That means removing all aerial wires. Specific information on Managing Risks can be found in the fact sheets:

Where that can’t be done, mitigation needs to take place. Such as marking the wires, and putting them on a hazard map you can give your pilot.

You’ve probably heard the term “reasonably practicable steps”; saving money is not a good enough reason to string a wire over a gully or road.

On the day of your safety briefing, you should discuss any wires or other hazards with your contractors. You should have written documentation detailing the information about any wire hazards in a contract.

You also need to plan for emergencies. Some questions to think about are:

  • What role will each person take?
  • Are there suitable places for an emergency landing?
  • Who has first aid training and a medical kit?
  • Are you within cellphone range?

Example of Different Duty Holders

This fictitious example is designed to illustrate the roles and duties in the Health and Safety at Work Act 2015.

Heli farm Spray (HFS) operates an agricultural spraying business that offers spraying services to local farms. Simon is the sole director and CEO (which is a senior person position required by the Civil Aviation Rules).

HFS employs Bob as the Chief Pilot (another senior person position required by the Civil Aviation Rules), and regularly contracts Ray, a self-employed pilot, to fly their second aircraft under HFS’s certification, when customer demand requires it.

HFS contracts to a number of local farms, one of these is Black Ridge Station (BRS) which is owned and worked by Joe.

  • HFS is a PCBU and a certificated aviation organisation conducting the business of performing commercial agricultural aircraft operations. HFS must consult, co-operate and co-ordinate activities with BRS and Ray, as they are multiple PCBUs with overlapping duties.
  • HFS’s employees are workers of HFS.
  • Simon, as the Director and CEO is an officer of HFS.
  • As Bob is a senior person (other than the CEO) in a certificated aviation organisation, this may also mean he is considered an officer of HFS for the purposes of the HSW Act.
  • Ray is a PCBU conducting his pilot contracting business as a sole trader.
  • As a PCBU, Ray must consult, co-operate and co-ordinate activities with HFS, as multiple PCBUs with overlapping duties.
  • Ray, as a sole trader is an officer of his business.
  • Ray is also a worker for HFS because he is engaged by HFS to pilot their second aircraft.
  • BRS is a PCBU as a working farm, and must consult, co-operate and co-ordinate activities with HFS, as multiple PCBUs with overlapping duties.
  • Joe is an officer as the Director of BRS.

Wire Hazard Management Among Duty Holders

Specifically, in regard to managing the risk of wires on the farm, all PCBUs must consult, co-operate and co-ordinate activities to ensure the work is undertaken in a safe environment.

BRS is required to provide a workplace that has its risks actively managed – wires should not be strung in a way that could cause a risk to aircraft while they are undertaking work, or these must be identified on a hazard map for the pilots.

HFS and its workers must alert BRS to any wires that could be a risk to the operation as they identify them. HFS must manage the risk to its workers.


CAA Vector Magazine

Vector has extensively covered wire strikes and how to avoid them. Check out the following articles for more information:



New Zealand Agricultural Aviation Association - a division of Aviation New Zealand, representing the agricultural aviation industry.

Total Aviation Quality - a company that regularly organises Bob Feerst’s wire strike avoidance courses in New Zealand.

Helicopter Association International - has a video, Surviving the Wires Environment, about wire strike avoidance on their web site.