Helicopter Safety and Familiarisation

This session covers aspects of helicopter safety, in particular the dangers associated with working with rotary-winged aircraft.

Before commencing this session you should read: Pre-hospital communication.

Context

In undertaking emergency medical or rescue work the helicopter and its crew may operate under difficult conditions but safety must underpin all missions.

When operated safely, helicopters provide an efficient and versatile work platform but it is important to remember that they have their limitations.

The pilot knows the limitations and safe workings of the aircraft better than anyone and they must always have the final word regarding safety.

There have been many avoidable fatalities around the world due to poor understanding of the potential dangers of operating in the vicinity of helicopters.

Helicopters are very susceptible to damage from foreign objects.

• Rotor downwash can dislodge any objects not secured to the ground and lift them towards the aircraft and damage either the airframe or the engine
• Airframe damage is usually confined to moving parts of the helicopter, i.e. rotors, and if the pilot suspects a rotor strike he must land at the earliest opportunity and inspect for damage.

All HEMS machines are powered by gas turbine engines which are very susceptible to damage from even small objects passing into the engine air intake.

Actions

The following actions should be carried out at least 10 minutes prior to the arrival of a helicopter:

✅ Keep all unnecessary personnel well clear of the area

✅ Ensure all loose objects in vicinity of landing site (twice the diameter of the rotor disc)are secured

✅ Conduct a thorough clean up of the area

Learning Bite

Remember that any unsecured medical equipment can become foreign object damage (FOD).

Clearance

Helicopter rotor blades are potentially lethal. In certain situations, such as high winds or uneven terrain, the clearance between the main rotor blades and the ground can reduce to strike any person or object within the rotor blade arc (the rotor disc).

The clearance height of the main motor differs between helicopters. With certain helicopters the rotor blades can oscillate vertically several feet when starting up and shutting down, creating a potential hazard to personnel entering the rotor blade disc at these times.

It is important that you are aware of the entry/exit points for the type of helicopter that is operating.

Danger Areas on the Helicopter

Helicopters have many danger areas that you have to be aware of:

Tail rotor

Depending on the type of helicopter the tail area may be unprotected and difficult to see because of the high rotational speed. In some helicopters the tail rotor is enclosed in a fenestron.

For safety, regardless of the type of helicopter, the trail rotor must be avoided. Personnel should never approach a helicopter from the rearward position or ‘duck under’ the tail boom.

Learning Bite

Never pass close to the tail or directly behind a helicopter that has its engine or rotors turning.

Radio antennae

The radio antennae may be located on the top or underside of the fuselage and underneath the tail boom.

They are capable of causing radiation injury when operating. They can be damaged by handling and due care must be taken when loading or unloading patients.

Main rotor

The main rotor can tilt close to the ground during normal operations. This clearance can be further decreased during operations on uneven or sloping ground and good situational awareness is paramount.

Several tonnes of downwash can be generated by the main rotor which can dislodge loose objects and cause FOD to the helicopter. Unsecured medical equipment can be blown away. Eye and ear protection is mandatory for the pre-hospital team, receiving team and the patient. When the helicopter is starting up and shutting down the rotor blades can oscillate vertically several feet, creating a hazard to personnel entering the rotor disc at these times. Permission must be sought from the pilot before entering the rotor disc.

Static electricity

In flight a helicopter can build up considerable static charge or electricity.

Severe shocks, giving minor injuries, have been experienced by personnel touching aircraft before it has been earthed and a charge in the region of 250 000 volts has been measured.

Approaching Positions

The aircraft must not be approached at any time without permission from the pilot (usually sitting on the right hand side of the cockpit). The rotor disc must not be approached or entered at any time without the express permission of the pilot.

All approaches must be made in the pilot’s field of vision and it must be remembered that entry points vary between aircraft.

Entry at 10 and 2 o’clock positions (as shown in the image to the right) is used for most helicopters, but some aircraft will have entry points at 3 and 9 o’clock positions.

Before approaching the helicopter, you need to seek approval to enter under the rotor disc. There are procedures that you have to follow when approaching during the day and at night.

During the day

• Signal the pilot by extending one arm from chest height with your thumbs up
• Only when the pilot returns with the thumbs up signal or a positive nod can the approach be made

At night

• Signal to approach by flashing a torch (directed at the ground)
• Wait for the pilot to flash the landing light as a sign of permission to approach

Sloping ground

Also, always approach the helicopter on the downhill side of any slope. Rotor clearance is significantly affected by sloping ground:

• Approach and depart the helicopter on the downhill side of any sloping landing point to avoid the main rotor
• If this involves walking around the helicopter to avoid the area of lowest clearance, then the only path is around the front of the helicopter, never the rear

Learning Bite

Never go beyond the side doors of a helicopter and always avoid the rear.

Other Dangers

Other dangers to be aware of include the following:

Image adapted from Shutterstock

1. Equipment

When carrying equipment to or from a helicopter, hold it horizontally and below waist level. Never hold it vertically and beware of drip stands.

Any long object must be carried between two people, one at each end to avoid inadvertent contact with the rotor.

2. Loose objects

Never reach up or chase after an object that has been blown away by downwash.

Ensure that hospital or first aid attendants keep back trolleys and stretchers at a reasonable distance while the helicopter is landing or taking off.

This will avoid loose articles being blown away and prevent debris being blown onto the patient.

3. Blinding

If blinded by dust or a blowing object when the helicopter is landing, taking off or before the rotors have stopped, immediately stop and sit down. Never grope towards or away from the helicopter.

Protect eyes by shielding with your hand or squinting.

Warn spectators to ensure protection against dust or blown debris.

4. Vehicles

No vehicles should approach the helicopter when its rotors are turning.

If it is absolutely necessary for a vehicle to approach a stationary helicopter, this must be done under specific direction from the pilot in command.

Helipad

Hospital helicopter landing sites and their security are the responsibility of the hospital trust.

It is usually security personnel who are tasked with ensuring helipad security, and once notified of an inbound aircraft, they will deploy to the designated landing area.

Security personnel will undertake the following tasks:

• Ensure that they are wearing high visibility jackets, have eye and ear protection
• Switch on the helipad lights
• Perform a visual sweep of the landing site and remove any loose objects or debris that might pose the risk of being thrown up by downwash and damaging rotors or airframe
• Remove any bystanders to a safe distance and ensure that no-one can approach the aircraft when it is landing (as shown in the image to the right)
• Ensure that any loose articles on hospital trolleys are secure and cannot be blown away by downwash from the rotors.

Personal Protective Equipment

The security staff should wear the following personal protective equipment (PPE):

High visibility jacket

Wearing a high visibility jacket ensures that the helicopter pilot is able to identify ground personnel and determine who is part of the receiving team and who is a casual bystander.

Eye protection

Glasses protect against eye damage from loose debris that might be thrown up by rotor downwash.

If debris is dislodged by downwash and you are temporarily unable to see, stop moving towards the helicopter, crouch down and take time to allow debris to settle and vision to clear.

Ear protection

Long-term exposure to aircraft engine noise may cause hearing damage; wearing hearing protection will minimise this.

The area should be free from tall obstacles such as pylons and a visual inspection for any wires, telephone or electrical, should be made.

Image via Shutterstock

The ground should be firm and as flat as possible.

The site should preferably be downwind of the incident so air traffic overhead is minimised as helicopters land into wind. This may not be possible if there is thick smoke and debris.

The landing site should be inspected for any loose articles or rubbish that might get blown and cause injury, or damage the airframe or engines of the helicopter.

Care should be taken to ensure that all personnel in the vicinity of helicopter operations have been briefed regarding helicopter safety. Particular importance should be placed on not approaching the helicopter until given authorisation from the pilot. Personnel should be cautioned against approaching the helicopter on landing sites with sloping ground.

Personnel should be issued with personal protective equipment in the form of high visibility clothing, eye protection and ear protection.

1. Greaves I, Porter K. Oxford Handbook of Pre-Hospital Care. 1st ed. Oxford: Oxford University Press, 2007.
2. Calland V. Safety at Scene. 1st ed. London: Mosby, 2000.
3. Eaton JC. Essentials of Immediate Medical Care. 2nd ed. Edinburgh: Churchill Livingstone, 1999.