The 10 Biggest Threats for Air Ambulance Helicopters

Helicopters have a lot of threats to manage on a daily basis. From tail rotors without redundancy, to all the moving parts and the aerodynamic counter-forces to actually stay in the air.

The biggest threats for air ambulance helicopters (and causes of accidents) aren’t actually mechanical issues however. They are more operational and environmental factors.

When we look at global aviation statistics, helicopters do not stack up well against fixed wing stats at all. Why? Well, there are a lot of reasons, some of which we’re going to cover here!

If we zoom in on the Helicopter Emergency Medical Services (HEMS) industry (or air ambulance, depending on your part of the world), the stats get worse.

Have a look at this data from the latest EASA Annual Safety Review:

Over half of the CAT A accidents and serious incidents in 2022, were in HEMS operations. The report also notes:

So why is this? What are the biggest threats for air ambulance helicopters, and are they going to stick around in the future?

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1) Controlled Flight Into Terrain

Controlled Flight into Terrain (CFIT) is one of the main reasons for the poor safety reputation of the rotary wing industry. CFIT happens when a plane or helicopter inadvertently flies into terrain, obstacles, or water, usually due to poor visibility conditions. Various safety organisations have linked the following to a risk of a CFIT accident:

Interestingly, the decision from helicopter pilots NOT to continue IFR has been a talking point for a very very long time. It has still not been properly addressed.

Various factors play in to this:

• Lack of viable helicopter IFR options or infrastructure
• Unable to carry enough fuel (more on this below!)
• Not feeling confident enough due to competency / recency issues.

How can we address this as an industry? We’ll cover this in the future, but unfortunately there is no clear cut answer at the moment.

2) Inadvertent Entry Into IMC

So while a planned conversion to IFR doesn’t happen enough according to safety statistics, the ‘unplanned’ version happens very often: Inadvertent Entry Into IMC (IIMC).

Pushon-itis is a big one here. Picture this: the crew are dispatched to a horrible accident on a motorway. Children are involved. All required resources are on scene, but a helicopter is required due to the severity of injuries. Everyone wants to help.

The air ambulance dispatches. The weather is great at base, but there are no weather observation stations near the scene. Enroute, the crew finds themselves descending more and more due to a reduction in cloud base. Radalt bugs are set to the mimimum allowed setting. The crew thinks to themselves “we don’t really want to descend any more than this”.

After flying for 40 nautical miles, with 2 miles to go, the weather becomes below limits.

What do you think could happen here? If we look at all accident reports from the last 20 years, there is a predictable course of action. Of course, the safest decision is to not get ‘sucked in’, declare the weather unsuitable and return back to base.

Unfortunately, the decision that’s made before these accidents happen is often to push on, as ‘we got this far, right?’. Sunk cost fallacy, pushon-itis, self induced pressure, hero-ism, macho attitudes, ego, and LOTS of other reasons play into this.

The deck is stacked against us if we allow primal urges to take over our brains. Situations like this (not just in the air ambulance industry) have led to countless IIMC events and often do not end well for anyone.

It’s these moments that define us as pilots. Do we listen to the emotional, or to the rational side of our brain? Do we safely return to be able to dispatch to a different job? Or do we push on while taking on an unacceptable amount of risk?

Of course there are always other solutions. Maybe rendezvous with an ambulance, or crew collection vehicle at a location where weather is suitable. However, this decision isn’t always made in the cases that have been widely researched.

The industry push to get helicopter pilots IFR rated, even the ones who primarily fly VFR, has been one of the attempts to address the issue. It’ll be interesting to see whether this change makes a substantial difference.

Having an Instrument Rating (IR) should make you more inclined to consider IFR as an option. But is it enough? Only time will tell as we get the data.

Does a pilot flying in poor conditions under high workload feel comfortable enough to rely on skills he only uses 3 times every 90 days for currency purposes?

Another issue is that going IFR usually means the mission can’t be completed due to distances to airfield, and the time it takes to conduct a full IFR approach procedure.

3) Lack of Weather Data

Weather is one of the most significant threats facing air ambulance helicopters. Poor weather conditions such as thunderstorms, heavy rain, fog, poor visibility, low cloud bases and strong winds, can make it difficult for flight crew to safely operate. Decision making is key here.

Even if the helicopter is allowed or able to take off and land, the flight crew may be forced to reduce altitude and speed, increasing the time it takes to reach the patient. In addition, it’s possible that the weather allows for a take-off, but a landing at the destination is not guaranteed. This makes the entire operation more complex, requiring more plan B’s, C’s, etc.

The benefit of a helicopter though, is that if at any point you’d rather be on the ground than in the air, you can select an ad-hoc landing site anywhere on the ground that is suitable, and land! Plenty of fixed wing pilots who would love to have that luxury!

The question is however what you were doing to require such a site. If the weather conditions are that bad, should you have been flying in the first place?

To this day, weather is still the largest obstacle to overcome for air ambulance helicopters.

Another factor is that air ambulances don’t usually fly to airports. This means that weather reporting facilities are generally not available. If you’re landing in the middle of nowhere, you might not even have an airport within the entire area! Weather decisions now have to be based on forecasts, which can be very unreliable. Good decision-making relies on accurate data!

This is especially true if you’re flying in an area where there are a lot of microclimates, such as near coastlines, ridge lines, mountains or forests.

The weather could be great before take off, but what if there is a massive front approaching with conditions that are unsuitable for safe flight. Do you take the mission knowing you’re going to strand the helicopter? We can’t always just look at a METAR / TAF and decide based on that, unless we’re flying to an actual airport, which is rare.

No situation is black or white, and lots of pilots will have a different opinion on various situations. Knowing where you are on the scale from very conservative to more risk-taking behaviour is helpful to debrief yourself after every flight, and to see where you can improve.

4) Drones and Birds

Helicopters fly low. Drones and birds fly low. A bunch of seagulls aren’t going to NOTAM their intentions. Neither is the kid that just got a new drone for his birthday.

Again, awareness, planning, and vigilant behaviour are the only remedies for threats like these. Working together as a crew and flying defensively to expect the unexpected can work really well to address these issues.

As we grow more experienced as pilots, it’s possible to become more complacent about issues that have not caused any harm to us over the years. You might not have had a bird strike after 35 years of flying in the same operating conditions. That unfortunately doesn’t mean you won’t have a bird fly into your rotor disc or engine today or tomorrow though.

From personal experience, drones have mainly been an issue during the landing stage into an uncontrolled site. People are excited to see a helicopter land and start filming, with either cameras or drones.

Bird and drone strikes have their own little part in global aviation accident stats, and will probably continue to do so. The only remedy is situational awareness and not letting our guards down.

5) Commercial and Self-Induced Pressure

The mud-flinging contest on whether it’s self induced or commercial pressure is kind of pointless. At the end of the day, pilots still make decisions that are affected by something that isn’t flight safety. How do we train ourselves to make decisions that are in line with a safe outcome?

Across the aviation industry, commercial and self induced pressure still has a massive impact on flight safety.

Why do pilots fly into mountains, take off in fog, or push on below limits and hit a power line? Why did they refuse to go back to base and live another day? The answer has been commercial or self induced pressure far too many times.

For air ambulances, the nature of the job is often one with lives at stake. They’re there to help. Training and awareness is the answer here. Being aware of the urge to push into conditions you’re otherwise not comfortable in, is crucial to address the issue. Would I lift if the patient wasn’t in the circumstances that they are currently in?

Most operation manuals mention the responsibility of the pilot to weigh off the medical risk of the patient to the aviation risk. But this shouldn’t mean that once someone is dying on the ground, we can just ignore the rules and do whatever we want to get to scene.

Interestingly, in some parts of the world, flight crew aren’t told about the type of patient, to protect them from emotional pressure. What do you think about this? You could argue that having all data available helps make the most informed decisions, but there are lots of counter arguments as well.

But it’s not just HEMS. It happens all across global aviation, in lots of different aviation sectors. Regulators will have to step in. Companies across the globe have to juggle profit making and flight safety. These are 2 factors that are often on opposite sides of an argument.

Plenty of accident reports and recent events (look at the B737 MAX) are comparable to asking the fox to guard the hen house. Businesses have 1 priority: profit. You can’t blame them for having this goal, they’re businesses for a reason. But flight safety has to be a priority too! Regulators need to step in and make sure that this responsibility isn’t an ‘option’, but a requirement.

6) Uncontrolled Landing Sites

The nature of HEMS means that most of the landing sites are uncontrolled. Uncontrolled landing sites pose a threat due to the fact that there are a lot of unknowns at the site, that can be hard to spot during the recce.

While tools are available to spot threats like power lines, elevation differences, or even covered reservoirs, there will always be a risk for things to be there that are hard to plan for, or spot during the recce. A farmer could’ve built a mast that takes a random power cable across a field, there could be a kid at the site flying a drone or a kite, etc. None of this could ever be planned for on a plate or pre-flight briefing, other than to expect the unexpected and be attentive throughout.

The other risk is brownout or foreign object debris (FOD). The risk of damaging public property or causing harm to people because of objects being blown around by rotor downwash is always a factor, and needs to be mitigated. If, during the later stage of the approach, downwash is observed to be a factor, a go around should always be considered.

7) Relatively Low Fuel Capacity

Fuel capacity = options! Decision making is always easier to manage when you have options. Unfortunately, (and particularly when it comes to IFR flight operations), helicopters often don’t have great fuel capacities. Especially when they’re also loaded with medical equipment, patients, and medical crew.

It’s a delicate balance between carrying enough equipment to be able to do the job, while also having enough fuel that ‘you might not use’. It’s a hard sell to someone who isn’t familiar with aviation, or has a mission to accomplish using a helicopter.

This have been made slightly better by more efficient helicopters that have been designed over the years. However, compared to our fixed wing friends flying the long tubes with wings filled with massive amounts of fuel, we still have a lot to improve on when it comes to fuel capacity.

Even something like an unplanned VFR to IFR conversion in flight comes with the question of ‘do we have enough alternate fuel’, ‘are we legal to convert to IFR here in regards to our fuel capacity’? Often, the answer is a pretty clear no due the nature of the job.

These are questions that are very necessary, but often stop pilots from safely converting to IFR, with the fear of forgetting something in the moment. Another reason to incorporate this into the planning stage. Although this could be difficult due to large amount of unknowns.

8) Flight Crew Fatigue

Fatigue is another significant threat to air ambulance helicopter crews.

From waking up by an alarm at 2 AM when the mission comes in, to flying in poor weather, low level, in a complex aircraft with lots of variables to consider, only half an hour later. It’s not a transition humans are designed for.

Not only this, but night shifts are often 12 hours long, with periods between 0200 and 0600. This has been proven to not only have long term health consequences, but it also comes with the challenge of dealing with the fatigue itself while flying at those times.

Luckily HEMS is slowly moving towards a multi pilot environment, where pilots can help each other and can cross reference data and decisions. There are still lots of air ambulances across the globe that are flown single pilot however. It will be interesting to see how this develops in the future.

9) Hostile Terrain

Then there’s terrain. Whether in congested areas or not, hostile terrain can be tricky to deal with. Depending on the country you’re in, most hospital landing sites require performance class 1 to be adhered to. While HEMS operating sites can be flown to using performance class 2, as we discussed in our performance class article.

This means that when flying to a hospital, extra care must be taken to make sure you’re flying the correct profile, with appropriate reject or go-around options available, if a malfucntion occurs. Not to mention not overflying hospital buildings, following noise abatement procedures, and ensuring a safe approach path with a headwind component.

During the approach, things like trees, masts, car parks, people, wires, buildings and vehicles can all present a threat. If you’re flying HEMS with only a single-engine aircraft (like sometimes in the USA), always making sure you have a safe forced landing area available in case of an engine failure can be a challenge.

10) Human Error

Human Error is still one of the largest factors influencing aviation. The only way we can improve this is by proper training, CRM awareness, flat cockpit hierarchies, and a Just Culture within aviation companies.

Proper decision-making, whether multi pilot or single pilot, is often the difference between a serious accident and a safe flight. All the threats discussed can be mitigated with rational and thorough decision making, preferably as a team.

We’ll cover this topic more extensively in the future, but human factors as a whole has a lot of different ways in which it can influence incidents or accidents. Factors like fatigue, personalities, stressors, distractions, teamwork and many others are all hugely relevant and will stay that way, until we all get replaced by AI…

Conclusion

Threat management will continue to be hugely relevant for the air ambulance industry. The threats discussed here are not an exhaustive list, but are the biggest factors that influence flight safety for helicopter flight crew.