External load

Part 133 in outline

In the US, external-load work needs a Rotorcraft External-Load Operator Certificate, with a chief pilot who has demonstrated knowledge and skill to the FAA. Advisory Circular 133-1B describes how operators apply and operate.

The operator writes a Rotorcraft-Load Combination Flight Manual. Its limitations include mass and centre-of-gravity limits, a maximum external load no heavier than was demonstrated, and airspeed limits. It sits alongside the RFM and its supplement, not instead of them.

Other countries have equivalent rules; the principles carry over.

Sources 1, 3

What the pilot must show

Each pilot must demonstrate knowledge and skill for the rotorcraft-load combination and carry a letter of competency or a logbook entry. The knowledge covered says what the job really is:

• surveying the area before operations start;
• loading, rigging and attaching the load;
• the aircraft's performance under the approved limitations;
• instructing the flight crew and ground workers;
• the load-combination flight manual.

The skill test is flown for each class of load the operator wants.

Source 1

Load classes

Who may be on board

During external-load operations Part 133 allows on board only flight crew, crew trainees, and people who perform an essential function in the operation or are needed for the work itself.

The pilot in command must brief all of them before take-off on the normal, abnormal and emergency procedures and the equipment in use. A lineman riding along is a crew member with a job, and needs to know what happens if the load is released.

Source 1

Hook systems

The cargo hook sits under the fuselage. On a long line there are two hooks: the belly hook holding the line, and a remote hook at its bottom end holding the load, each with its own release.

Certification rules require a primary quick release with its control on one of the pilot's primary controls or equally accessible, and an independent backup release, isolated from the primary. Know which switch opens which hook: confusing them drops the line instead of the load.

Sources 2, 3, 5

Vertical reference

Long-line work is often flown looking straight down out of the door at the load, from the right seat. That's a different way of flying: reference comes from the line and the ground below, not the horizon.

The pilot's position on the right affects lateral CG. Some aircraft have a bubble window or doors-off configuration for it — each with its own supplement.

Sources 3, 7

Flying the long line

A long line puts the aircraft above the trees, the dust and the people on the ground, and the load where you can place it precisely. The price is a hover out of ground effect for the whole job — plan on HOGE performance.

Looking down, it is easy to lose the picture of the aircraft itself: a slow drift, a descending hover, a skid closing on a slope. Glance up and out at regular intervals, and keep the aircraft's height above the ground as well as the load's.

Sources 3, 8, 9

Load behaviour

Loads oscillate, spin and can fly — a light, bulky load can rise towards the aircraft at speed. Each load type has a speed at which it flies stably and speeds at which it doesn't.

Small, early corrections damp an oscillation. Large ones feed it. And a load that won't settle is a load to set down or release.

Source 3

Pick-up and set-down

Pick-up: hover over the load, take up the slack slowly, and lift vertically, with no drift. Then pause: is the load stable, and is the power what you expected? Only then move off.

Set-down: place the load, lower until the line is slack, then release. A load still in tension when it's released springs the line; a line still attached to something fixed is a tether.

A taut line plus a drift is the rollover setting — the next two stories.

Sources 9, 10, 11

Jettison

The release exists for the moment the load threatens the aircraft: an oscillation that won't damp, a load flying towards the rotor, a line snagged, an engine problem with the load still on.

Decide before you lift what would make you release, and where the load would fall. Route so that it falls on nobody — never over people, vehicles or the ground crew. The supplement says what the aircraft does in each case; your brief says what you'll do.

Sources 3, 5

Fuel planning

Fuel is mass. Every kilogram in the tank is a kilogram the hook can't lift, so external-load work is often flown with little fuel — and burned fuel turns into load capacity as the day goes on.

The trade is margin. Plan refuelling around the job rather than the job around the tank, know exactly what the low-fuel warning leaves you, and recompute the heaviest lift each time the fuel changes. Fuel burn also moves the centre of gravity.

Sources 7, 8

Ground crew and signals

US workplace rules for helicopter loading set out the basics:

• a briefing before each day's operation for pilot and ground crew;
• constant, reliable communication with one designated signaller, distinctly recognisable from everyone else;
• static on a suspended load discharged before anyone touches it, or rubber gloves worn;
• no loose clothing that can flap in the downwash.

The ground crew's safety and the load's are the pilot's responsibility too.

Sources 1, 6

Human external cargo

Carrying a person as the load is called human external cargo (HEC). The FAA's guidance treats it as a separate approval, with attaching equipment certificated for carrying people — a cargo hook kit approved for freight is not approved for a person.

A person doing an essential job in the operation may be carried as a Class B load, in a single- or multi-engine helicopter. Anyone else needs Class D, which requires a helicopter able to hover with one engine inoperative. The training, equipment and approvals are the operator's to hold, never the pilot's to improvise.

Sources 1, 3, 13