Jet Blast Safety Distances for Ramp Workers

Jet blast safety distance on the ramp is not one number. It depends on the aircraft type, the engine's thrust setting and where you are standing. The distances for each type are published by the aircraft manufacturer and drawn into your employer's ramp procedures; this article tells you how to read them, how to recognise a live aircraft, and the habits that keep you on your feet.

What jet blast and intake suction do to a person

A jet engine does two things to the air around it. At the front it pulls air in. At the back it pushes it out, hot and fast. Both can kill.

Intake suction: at idle, the inlet is already pulling. At higher thrust it will lift a person off the ground and pull them in. Loose items go first: a hat, a headset, a clipboard, a bag of FOD. A person follows.

Jet blast: behind the engine, the exhaust is hot and moves faster than any storm wind. At idle it will push you over and send a baggage cart rolling. At breakaway thrust, which is the power a pilot uses to start the aircraft moving, it will throw a person across the apron and tip a belt loader. The blast does not stop at the engine. It continues back for a long distance and spreads sideways as it goes.

Propellers are different and worse in one way: you cannot see them when they turn. A turning propeller looks like a faint disc, or like nothing at all. Prop wash behind it has the same effect as jet blast. Helicopter rotors add a third danger: the rotor disc dips at the front and sides, and the tail rotor is almost invisible.

Recognising an aircraft that is not safe to approach

Before you think about distances, you need to know whether the engines are, or could be, running. Three signals tell you.

• Anti-collision lights (the beacons). Red flashing lights on top and underneath. When they are on, the engines are running or about to start. Nobody approaches an aircraft with beacons on unless they are part of the start or pushback team and in position.
• Chocks. Chocks in at the nose and main wheels mean the aircraft is parked. Chocks out means it is about to move, or already can.
• Cones. Cones around the engines and wingtips mark the hazard area while the aircraft is on stand. Cones removed is another sign that departure is near.

The sequence on arrival is the same everywhere, in the order set by your employer's procedure: the aircraft stops, the engines spool down, the beacons go off, the chocks go in, the cones go out. Only then does the ground crew approach. On departure it runs the other way. Read the signals before every approach. Do not assume the aircraft is the same as it was two minutes ago.

Danger zones around engines, propellers and rotors

Each aircraft type has a danger area diagram. The manufacturer publishes it in the aircraft's ground operations documentation, and your handling company copies it into the stand plan and the training you receive. The diagram shows two shapes for each engine: an intake hazard zone in front of and to the sides of the inlet, and a jet blast zone behind that grows with thrust. There is usually one diagram for idle and one for breakaway power. The blast zone at breakaway is far larger than at idle.

Learn the diagram for every type you work. The zone behind a large twin-engine wide-body is nothing like the zone behind a small regional jet. Tail-mounted engines blast higher and further back than wing-mounted ones. Propeller aircraft have a full-circle hazard at the propeller disc, plus prop wash behind.

On the stand, these zones are usually drawn as lines on the apron: the equipment restraint line and the stand safety lines. Equipment stays behind those lines until the aircraft is stopped and safe. People do too.

Distances that keep you standing

There are three distance rules you can carry in your head, and none of them is a number.

1. Never in front of an inlet while the beacons are on. The intake zone is the one place on the ramp where you get no second chance. If you must cross in front of a parked aircraft, cross outside the cones.
2. Never behind a running engine, at any distance you can walk in a minute. If you can feel warm air, you are too close. If you can hear the engines change note, the thrust is rising and the zone is growing.
3. Never under or beside a propeller disc, running or not. Treat a stopped propeller as if it could turn. Walk around the wingtip, not under the wing, on propeller aircraft.

Everything else comes from the diagram for the type and from the lines painted on the stand. If you are not sure which diagram applies, ask the lead before you step out. The ground operations manual published by IATA is the reference most handling companies build their procedures on, and your employer's version is the one that applies to you.

Two more habits. Face the aircraft when you are near it, so you see the beacons change. And look behind you before you reverse any vehicle, because the aircraft on the next stand may be starting.

The same discipline, applied to the whole approach, is the subject of preventing ground damage to aircraft. The signals that tell a pilot you are clear are in aircraft marshalling signals for new ramp agents.

Example: the pushback that started early

Say you are on the ramp on a busy afternoon. The aircraft on stand 23 has its door closed and the bridge is retracting. You are driving a belt loader back from stand 24, next to it, and your route runs behind stand 23's tail.

The beacons on 23 are on. You did not see them come on, because you were loading. The tug is connected, and the headset operator is walking the aircraft back. You are about to drive across the line behind the aircraft.

The right action is simple, and it has to be instant: stop, stay behind the stand safety line, and wait. The pushback crew will clear the aircraft onto the taxi lane, the engines will come up, and the blast will sweep exactly where you were about to drive. A belt loader is heavy. It still moves when a wide-body's engines come up behind it.

Now the hard part. Say you had already crossed the line when you saw the beacons. The rule is the same: get out of the zone, away from the tail, as fast as the vehicle allows, and tell the lead on the radio. Never try to beat the blast by driving through it. If you are on foot and caught in the open, your employer's procedure says what to do; follow it, and never shelter behind loose equipment, because the equipment will move too.

Afterwards, this goes in a safety report, so the station can close that route during pushback.

When this does not work

Rules and lines do not help when you cannot see them. At night, in rain or in a snowstorm, beacons are harder to spot and painted lines are gone. Slow down, stay on the marked vehicle lanes, and treat every aircraft as live until you have confirmed it is not. In lightning conditions the ramp may stop altogether; what ground crew must do when the ramp stops for lightning covers that.

And they do not help if you are in a hurry. Almost every jet blast injury has the same story: somebody took a shortcut behind an aircraft to save thirty seconds. The ramp safety pillar, airport ramp safety for ground crew, is built around that one idea.

Learn this in five minutes

The track Moving Around Aircraft Safely covers recognising an aircraft that is not safe to approach, what beacons, chocks and cones tell you, the danger zones around engines, propellers and rotors, the distances that keep you standing, and working under the wing and at doors. Five lessons, each one a situation on the ramp.