Utility and wire-environment work

Wire strikes in numbers

Knowing isn't seeing

The most uncomfortable figure in the ATSB's study: in most wire strikes the pilot already knew the wire was there. Knowledge from a briefing or a map doesn't protect you once your attention is on the task.

Wires get hit after a turn, on the second pass, when a new task begins, or when there's a second wire nobody mentioned. Re-brief each wire before each pass that goes near it, and say it out loud.

Source 4

Patrol and construction

Patrol is flown slowly alongside a line, looking at it — so the pilot's eyes are on the structure, not the path ahead. Construction and stringing put the aircraft close to towers and lines under tension, often with a load.

Both depend on a briefed method: speed, height, which side, and who watches what.

Source 1

Flying a patrol

A patrol spends hours low and slow — inside the height-velocity curve — with the pilot's eyes drawn sideways to the line. That's why the method fixes the height, the offset and the speed in advance, and why an observer, where carried, does the looking at the line.

The hazards are the ones the patrol isn't looking at: crossing lines, a distribution line tapping off, the next span's change in height, and terrain rising ahead. Plan the turns at each end before you reach them.

Sources 2, 4, 5

Stringing

Stringing pulls a light line through the structures of a new power line, to be followed by the conductor itself. The helicopter is flying with something attached that may be in tension and fixed at the other end — Class C external load.

The method is designed to keep the rotor clear of the structures and the aircraft out of its own dust. The Key Lake rollover and the Woomera collision both happened during stringing.

Sources 1, 6, 7

Supervision of the method

The ATSB also found that the indirect supervision given to the newly trained pilot did not reveal that a modified method was being flown.

For a pilot, that means the method you were taught is the one you fly until it is changed deliberately, with the people who wrote it. For an operator, it means checking how the job is actually being flown, not just that training was done.

Source 1

Spraying

Aerial application puts the aircraft lower than almost any other work, and the ATSB's data put most wire strikes there. The pattern repeats: a run, a turn at the field boundary, another run — and boundaries are where the wires are.

Survey the field and its edges from height before the first run, mark every wire, and plan the turns away from them. The aircraft gets lighter with each load; the wires don't move.

Sources 2, 4

Survey

Low-level survey flies long straight lines at a constant height, often over unfamiliar ground and sometimes with equipment towed beneath. The line was planned on a map; the wires crossing it may not be on the map.

Look ahead along each line before flying it, add every wire found to the plan for the next line, and resist descending below the planned height to improve the data.

Sources 2, 4

Inside the height-velocity diagram

Most utility work is flown where the height-velocity diagram says an engine failure may not end in a safe landing. That is accepted by necessity, so it has to be managed: transit at height, minimise the time spent low and slow, and keep a landing option in mind for each phase.

Brief it — for yourself and any crew — as part of the job, not as an afterthought.

Sources 2, 5

Crew lookout

Where a second crew member is carried, split the work: the pilot flies and looks ahead, the observer looks at the task. Agree the calls in advance — what a wire call sounds like, with its direction and whether it's above or below — so a call needs no interpretation.

Keep the cockpit quiet near hazards. Conversation is for transit.

Sources 2, 4

Using LowOps in wire work

Use LowOps before the flight as much as during it: look at the work area for recorded wires and structures, then compare with what you find on the reconnaissance. Record the hazards you find that the map doesn't show.

In flight, an alert is a prompt to look, not a clearance. And remember what the ATSB found: most pilots who hit wires knew they were there. An app that tells you about a wire is only useful if it changes what you look at.

Sources 1, 4