Don’t Let These 8 Helicopter Landing Site Threats Surprise You

Landing a helicopter safely doesn’t just mean a smooth and accurately flown approach – it also means having a full understanding of the landing area around you 🚁

The goal here is to have a mental picture of the landing site that is as close as possible to the “actual picture”.

But the truth is, not every threat is obvious 🚨

Initially a site might look safe: a flat surface, enough space to land, and nothing else that jumps out. But hidden threats can quickly turn a normal landing into a not-so-great situation…

Landing site selection is a challenge that gets easier with experience, but can still cause issues for pilots who have done it for 30 years ⏱️

It’s usually not the obvious threats that can catch you out, it’s the ones you didn’t see coming.

Today, we break down eight landing site threats that have challenged many pilots:

Flying the approach is one thing, but actually landing safely is another!

Let’s dive in ⤵️

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1️⃣ Wires, wires, wires

Wires are usually the main threat that comes up any time you talk about HEMS safety for more than a few minutes.

It’s tricky, because despite all of us being hyper aware of how disastrous a wire strike can be, it’s a threat that’s always looming in the background.

Sure, high tension pylons that are shown on aviation charts are easy to identify and manage. You could use the pylons as an aiming point so you’re always visual with the threat / highest point. Or, discuss go-around options like specific turns etc.

But…

I and many other pilots have seen smaller domestic wires after starting the approach phase, which were not identified during the orbit / recce. We covered the threats of wires here:

Preventing Wire Strikes: 10 Key Principles for Helicopter Pilots

You won’t see them on aviation charts, you might not find them on national wire GPS overlays, and spotting them can be a #%}%.

On Night Vision Goggles it becomes even more important to include the entire crew in building a shared mental model on what the threats look like. Someone might see something that you hadn’t, and vice versa!

2️⃣ Unpredictable Bystanders and Animals

We generally have 3 “grades” of HEMS landing types:

🔸 Alpha Landings: A short walk away from the scene
🔸 Bravo Landings: A short run away from the scene
🔸 Charlie Landings: A short drive away from the scene

Of course the aim is for an Alpha landing, provided the threats can be mitigated and the risk profile suits the benefits you get from reaching the patient earlier.

If we decide to go for a Bravo or Charlie, it’s usually due to the nearest suitable site being far away, or the threat that keeps on giving: people!

From children running into the landing site, dog walkers throwing that ball one more time, runners with noise cancelling headsets that somehow cancel out 90+ decibels, and the list goes on 😁

The problem here is, you can isolate and mitigate a wire in the go-around or undershoot, but you can’t manage someone on the ground from the cockpit.

We covered threat and error management here:

Keeping it Simple: Threat and Error Management as a Pilot

The most unpredictable and “hardest to manage” threat is the general public.

3️⃣ Foreign Object Debris (FOD)

FOD doesn’t sound like a big deal, until you’re in a tight site and an unspotted small bag suddenly rockets up into your rotor disc.

The trouble with FOD is that it’s often overlooked because it feels so minor. However a plastic sheet, loose piece of string, or even a child’s toy can become a serious hazard once rotor wash gets involved.

Unlike at an airport, where FOD checks are routine, we land in environments where no one has prepared the site for us. Parks, roads, fields, schoolyards; there’s always a risk of debris that can get ingested by the engines or cause main or tail rotor blade damage:

And don’t underestimate how far things can travel. Rotor downwash can lift or suck in objects from quite far away, and send them flying.

We covered rotor downwash in detail here:

Understanding Rotor Downwash: The Ultimate Pilot Guide

This is why an overhead recce is so important, especially at more complex sites. Look for anything that looks light, loose, or like it doesn’t belong, and discuss them with your crew.

Medical crew in the back might have a better view of what’s tucked behind a hedge or fence line.

4️⃣ Limited Go-Around Options

It’s one of those things we often take for granted: the ability to go around if something doesn’t feel right.

But in HEMS or remote ops, especially at confined or sloping sites, you have to set up the approach carefully to make sure that option exists.

Trees, wires, buildings, or rising terrain can all restrict your go-around path. If your escape route isn’t clear, and you haven’t briefed it, you’re now committed to a landing you’re not happy with.

That’s a dangerous place to be, which we covered here:

The Trap of Plan Continuation Bias

One thing that helps: fly every approach with the question in mind: “Can I still get out of this?” If the answer becomes “no” at any point, you need to be either committed to land, or fly the go-around.

Visualising the go-around path from multiple points on the approach is a habit that separates the safe pilots from those relying on chance.

Make sure the crew knows your intentions. If time is limited, even a brief “go-around will be a right turn away from terrain, then a climbing left turn” gives everyone the same picture before you start the descent.

If you ever find yourself on the approach realising your go-around plan doesn’t work anymore, it’s time to make some decisions!

5️⃣ Variable Wind Effects and Turbulence

On approach to an elevated helipad or on a hill, you might have a stable headwind all the way in—until you hit the edge of the hill / building. Then the aircraft lurches. Controls go light. And just as quickly, it settles again.

What just happened?

That’s the wind demarcation line: the invisible boundary where laminar flow separates from turbulent air spilling over the structure:

Above that line, you’ve got steady (often rising) flow. Below it: mechanical turbulence, downdrafts, etc.

Offshore platforms, rooftop pads, hospital helidecks, they all have their own version of this.

There are generally three main factors that affect what the demarcation line looks like:

🔸 The wind velocity
🔸 The angle of the wind striking the slope / structure
🔸 The angle of the slope / structure

Annoyingly, this matters most where you’re the busiest: late final, transitioning to the hover, landing. Turbulence here can cause overcontrolling, drift, or even loss of tail rotor effectiveness.

So how do you handle this? Anticipate it! EASA published some great material on this here.

Some operators publish turbulence zones and predicable wind patterns for a specific landing site or helipad. Choose an approach path that crosses the demarcation line at a predictable point, preferably with a height and power margin.

On top of the effects of structures and slopes, wind can be different locally as well, we covered downwind approaches here:

The Downwind Approach: A Silent Killer

6️⃣ Hidden Obstacles at the Landing Site

You’ve completed the recce, you’ve flown the site before. As you enter the final stage of the approach, something unexpected enters your field of view: a wire, a post, an overhanging tree. You missed it.

Why?

Because not all obstacles are obvious from the air. Some are short, unlit, or camouflaged. Others only become a noticeable when you’re at a lower height during your descent path.

Think wires between rooftops, poles, antennas, or even a rising terrain gradient that hides obstructions until the last bit of the approach.

These aren’t just annoyances. They’re real hazards. Every year, rotorcraft strike obstacles that weren’t spotted in the brief or visible on the chart resulting in Controlled Flight Into Terrain (CFIT). In low-level operations, assumptions can make your life hard!

So what do you do?

Build a habit of scanning for threats. Use different angles on the recce, not just one.

Brief the crew to call out anything odd, even if it seems trivial. If the landing site is new or cluttered, fly a go-around path that lets you reassess the situation.

What ruins your day isn’t the obstacle you see. It’s the one you didn’t!

7️⃣ Covered Reservoirs

This one still haunts me sometimes after receiving various briefings from experienced HEMS pilots: covered reservoirs.

More common in the UK, but also very relevant in Australia, the USA, and Europe. They are designed to protect water quality and integrate the reservoir better with the landscape around it.

They basically look like a “perfect” field: flat, wide, not sloped, and no surroundings other than a few suspicious pipes…

But it’s likely it won’t hold the weight of the helicopter if you were to land on one of them.

Here’s how to spot them:

🔸 Unusual Isolation: They’re often located in open areas with no direct public access: fenced off, or surrounded by a buffer zone. If you see a flat area with no nearby buildings, roads, or activity, it could be a covered reservoir.

🔸 Symmetry and Shape: Covered reservoirs tend to be perfectly square or rectangular, with sharp edges.

🔸 Uniform Texture or Vegetation: If it’s grass-covered, the turf might appear uniform, trimmed, or artificial, sometimes greener than surrounding areas because of moisture retention.

🔸 Lack of Surface Details: No trees, no structures, no obstacles: just a large, flat, featureless surface.

🔸 Fenced Perimeter or Warning Signs: If there’s a surrounding fence with signs, or a perimeter road, it could be a covered reservoir.

🔸 Map overlays: Covered reservoirs are depicted on our HEMS overlay software in the UK. You can spot them on satellite images based on pipes, vents, hatches next to the field.

🔸 Raised Embankments: Some reservoirs are slightly elevated and have sloped edges or berms, this might be visible on the approach.

8️⃣ Drones and Birds

Birds and drones are small, but the risk they bring is not. If you’ve got any doubt, delay the landing and verify what the flying object you spotted actually is. They can ruin your day in a second if you’re not paying attention.

Birds are unpredictable. Gulls and pigeons are the usual suspects near cities and hospitals, but you’ll also find birds of prey hovering near rural sites.

We went through birdstrikes and how to avoid them here:

The Threats of Bird Strikes and How to Mitigate Them

Drones are a newer problem. They’re small, hard to see, and sometimes flown by people who don’t realise they’re near an active landing site.

I’ve even seen drones being used at our landing sites during startup. The general public often doesn’t see drones as a threat to planes and helicopters, it’s up to us to manage that.

So what can we actually do to mitigate these?

🔸 Always keep an eye out for birds and drones, especially near cities, hospitals, and coastlines.

🔸 If you see a flock of birds, don’t just hope they’ll move, go around or hold off.

🔸 If someone spots a drone nearby, treat it like a real threat, not a nuisance.

🔸 Use NOTAMS / BIRDTAMS and people with local knowledge to find out about usual bird activity.

Conclusion

The challenge with off-airfield sites is that they don’t come with a briefing pack. There’s no tower. No marshaller. No guarantee that the nice flat bit you’re looking at is actually safe to land on.

That’s why the most skilled pilots are good at spotting threats before they become problems.

Some threats are obvious: wires, turbulence, FOD. Others are subtle: bystanders you didn’t see, obstacles that only appear when it’s too late, or a site that looks perfect… until it isn’t!

If there’s one takeaway, it’s this:

Build a habit of being suspicious.

If something looks too good to be true, dig deeper. If the go-around isn’t clear, don’t continue. If your gut says “this doesn’t feel right,” back up and reassess.

Most of all: get the crew involved, they’ll see things you won’t. And vice versa.

Because the biggest threat isn’t the one you see, it’s the one you didn’t even think to look for!