Drone Versus Airplane in Search: Flight Debrief and Thoughts

I recently flew a missing Alzheimer’s patient search in FIRE DEMON 1 in an area that created interesting challenges in both the airplane and for drones on the ground.

You know I’m a big proponent of drones in public safety, but in this situation, I found myself asking Command to bring all the drones, if any, to the ground as we conducted flight operations.

The Actual Situation

We received a dispatch for a 75-year-old man missing after wandering off from home the day before. He had already spent one night in the forest in the rain.

The search location was up against the Blue Ridge Mountains in a quickly rising terrain.

Command did have ground troops out searching and finding clues along the way. We had a general direction of travel.

Altitude Considerations

Right above the search area, there was a tower that extended up to 3,809 MSL. The peak was at 3,564 MSL.

In the airplane, I have two choices; I can either fly over the mountain and descend the sides, which is not smart or fly along and over the search area across the terrain.

As I approached, I could see a road at the top of the mountain, but would a drone pilot take off from the high ground and search down?

An issue with the drone is that the drone pilot and airplane pilot are talking at two different altitudes. The drone altitude is generally measured in Above Ground Level (AGL), and in the airplane or helicopter, altitude is Mean Sea Level (MSL).

For drones, even the AGL data is misleading since it only applies to the AGL above the takeoff point and not the actual height above ground level.

So if a drone pilot established a Landing Zone (LZ) at the top of the mountain, their altitude as they descended the mountain face would show a negative number. Even if the drone pilot departed along the side of the mountain, their altitude could show 400 feet AGL, but as they moved away from the mountain the drone would actually be at a higher true AGL.

Unlikely VLOS for Drone

The area was also heavily wooded, so it was unlikely a drone pilot would have VLOS on the drone and fly by telemetry alone. This search is a good example of why that is dangerous. If the drone pilot does not have the required CFR 107.31 VLOS, it is possible they would not be able to see and avoid the airplane, even though they might be able to hear it.

Even if they were standing at the Command Post, the drone would not take long to exit VLOS, given the trees and nearby ridges.

No CTAF for Drone and Manned Aircraft Pilots

Without a Common Traffic Advisory frequency between drone pilots and airplanes, there is no way to communicate airspace.

While we were communicating with Command on the public safety statewide frequencies, there was no way to know if a drone pilot that wanted to assist with the search would be in the area but not have a public safety radio.

I’m a big proponent of VHF radio communications between public safety drone pilots and manned aircraft above to coordinate airspace. As a manned pilot, I don’t want to block drones; I want to coordinate with them because there is almost zero chance I will see and avoid the drone. I don’t want to end up like this.

Communication is key, but there is a good way to accomplish this since the FCC refuses to allow drone pilots to use a VHF radio to transmit legally.

How Low Can I Fly in the Airplane or Helicopter

Many people have the incorrect assumption that the airplane can’t go lower than 1,000 feet AGL or 500 feet AGL when the reality is I can fly lower in certain situations.

I would say a heavily wooded area alongside a mountain is sparsely populated, and in that case, I could fly as low as I wanted to but not closer than any person, vessel, vehicle, or structure I could see. Read CFR 91.119.

Remember that just because I might be compliant to do that does not mean I regularly would. But in this case, there might be times I could be closer than 500 feet AGL, and I was a couple of times.

Pilot Thought Process

As I approached the area and saw the actual terrain and tower, I was concerned about whether winds might be coming over the top of the mountain that could create a strong downdraft since we would be operating on the leeward side.

I was also concerned about getting my bearings of the tower and search area. So I made one pass with the search area on my side to picture it, and then I went around the tower and over the mountain.

Given all the factors I decided the best approach would be to fly parallel along the face and do wingovers in the turns to stay close to the search area and within the corridor, I felt was safe for operation.

As you will see, I came back again and made another pass over the mountain top after we received a new GPS coordinate of a sighting.

Herein Lies the Problem

When we are flying on a search, my focus as the pilot is entirely trying not to get us killed by doing something stupid in the airplane. This leaves the Tactical Flight Officer (TFO) sitting next to me to be primarily responsible for searching on the ground.

When I put the TFO closest to the target, I cannot see out the right side of the plane. So if a drone appeared, there is no way I could see it and take evasive action. The TFO would probably not see it since their focus is down on the search area.

I am entirely dependent on the drone pilot remembering CFR 107.37 and yield the right of way.

“(a) Each small unmanned aircraft must yield the right of way to all aircraft, airborne vehicles, and launch and reentry vehicles. Yielding the right of way means that the small unmanned aircraft must give way to the aircraft or vehicle and may not pass over, under, or ahead of it unless well clear.

(b) No person may operate a small unmanned aircraft so close to another aircraft as to create a collision hazard.”

I have to trust that the drone pilot on the ground understands the actual MSL altitude of the drone, not AGL and that the drone pilot is aware I could be operating closer than 500 feet AGL in the sparsely populated areas of the search.

I also have to trust the drone pilot has compliant VLOS on the drone at all times.

The State Highway Patrol helicopter was over the area earlier and was lower than 500 feet AGL while conducting their search.

Safe Ending

This incident had a safe ending with the missing man being located. I wound up flying directly over him twice but never could see him with the dense tree cover.

If you’d like to read the flight debrief report, you can click here.

These types of situations are always great learning events.