We are very pleased to introduce the first safety promotion video by Bruce Webb, Director of Aviation Education at Airbus Helicopters, badged ESPN-R. In this video you will learn that wearing helmet protects against birdstrike and offers some degree of protection against collisions with small drones.
Why wearing a helmet is important?
Imagine the outcome on an in-flight collision with a bird or a small drone if the pilot were not wearing a helmet with the visor extended.
Fortunately, many helicopter flight crew members are already wearing helmets.
And while there are no civil regulations which require us to wear them, they are certainly an important piece of personal protective equipment.
Small helicopter windscreens aren’t designed to sustain Birdstrikes
Standard category helicopters – those weighing 3750 kilograms or less – which are the most common helicopters, have virtually no requirements which specify windscreen strength or resistance against birdstrikes. While transport category helicopters – those weighing more than 3750 kg – do have such a requirement. Basically, the regulation states that the aircraft must be designed to withstand the impact of a 1 kilogram bird – which is 2.2 pounds – at VH, the speed an aircraft will maintain in level flight using maximum continuous power.
But we know that many birds weigh considerably more than 1 kilogram. Hawks, eagles, buzzards, geese – often weigh much more. And some species of birds weigh 15 times as much. Combined this with the fact that the majority of bird strikes occur below 2 000 feet AGL – in the same airspace we often use – means that birds pose a serious threat to helicopters.
Collisions with small drones?
And today, we have the additional hazard of UAS – Unmanned Aircraft Systems – often referred to as drones. In most countries worldwide, these small drones are allowed to be flown as high as 400 feet AGL at speeds up to 100 miles per hour (*) while weighing as much as 25 kilos – 55 pounds. (*) The European requirements (Easy Access Rules for Unmanned Aircraft Systems (Regulation (EU) 2019/947 and Regulation (EU) 2019/945)) adopt a risk-based approach that lead to a combinations of measures to limit the risk of collision. A general speed limitation was therefore deemed not necessary. Only two classes of drones have a speed limit: CO and C1. The limit is 68 km/h (19 m/s). It was adopted to address ground risk and security issues. And beyond their sheer size and speed, these drones are constructed of materials which offer a much greater potential for aircraft damage that the flesh and bone of a bird.
The main messages
Remember, the most stringent standards for helicopters do not account for bird larger that 1 kilogram, with an impact velocity above VH. And these are only required for transport category helicopters. The smaller helicopters – which most of us fly – are completely exempt from such regulation. So we are all at risks from the potential penetration of a large bird or from most any drone. And keep in mind that the mass, velocity and construction materials of a drone make them more likely to penetrate a windscreen or damage the helicopter in some other way.
So what can we do to minimize the catastrophic consequences of an object penetrating the cockpit and potentially incapacitating the pilot?
The most effective method is to simply wear a helmet with the visor extended to protect your head and eyes.
Wearing a helmet is not a sign that helicopters are dangerous but rather an indication that you are taking reasonable precautions to enhance safety for everyone.
- Use all information resources available about migratory routes and bird concentrations and address the bird strike risk in flight preparation.
- Check NOTAM (BIRDTAM) and ATIS regarding bird activity at departure and destination.
- If there are two pilots, discuss emergency procedures before departure.
- Respect if possible, bird habitats. Avoid flying in or into known areas of bird concentration, like wildlife sanctuaries, coastlines and landfill sites (especially in spring and autumn) and fish packing facilities.
- Transits over areas of wetlands and inland water areas, such as lakes and ponds, should be avoided and if this is not possible, the 2500 feet AGL minimum should be aimed for.
- Coastlines should be crossed at 90 degrees to give minimum exposure to bird activity which is usually greatest on cliffs or at the waterline. Fly above 2500 feet AGL when practicable. Expect to find birds in cliff or ridge soaring.
- The greater the airspeed and heavier the bird, the greater is the risk of a bird strike and resultant damage. The slower the bird wing beat frequency, the larger the bird.
- The higher the speed, the greater the chance of a strike and the greater the energy of the impact!
- Birds of prey have been reported to attack gliders and other aircraft - yes, with intent!
- Bird flocks represent the highest risk of bird strike, both regarding probability of encounter and severity of damage.
- After take-off, increase altitude as quickly as possible and fly above 2500 feet AGL as planned, when practicable. Fly higher at night when possible, since birds also tend to fly higher at night.
- Departure from cruising altitude for landing should be completed as late as possible to avoid flying low level for any extended time.
More information is provided in the EASA Rotorcraft Community Bird Strike article and in the EASA SIB 2021-07 Bird Strike Risk Mitigation in Rotorcraft Operations.
EASA Easy Access Rules for Small Rotorcraft (CS-27), no Birdstrike requirement.
EASA Easy Access Rules for Large Rotorcraft (CS-29), CS 29.631 Birdstrike: “The rotorcraft must be designed to assure capability of continued safe flight and landing (for Category A) or safe landing (for Category B) after impact with a 1 kg bird, when the velocity of the rotorcraft (relative to the bird along the flight path of the rotorcraft) is equal to VNE or VH (whichever is the lesser) at altitudes up to 2438 m (8 000 ft). Compliance must be shown by tests, or by analysis based on tests carried out on sufficiently representative structures of similar design.”