11 Feb Airstrip Evaluation
I was eager to explore new places after installing a brand new set of 31” Bushwheels. My first off-airport destination was a 4100′ high alpine hilltop located in the Talkeetna Mountains. After a few passes and go-arounds, I landed. It was just me and my airplane and the countless wild summits that stretched to the horizon. I was inspired.
Although I pulled off the landing, I made several rookie mistakes. My approach was too fast. I missed my intended touchdown point. My brakes were marginal. The mains were over-inflated. Sharp rocks left cuts in my new tires, and I wasn’t aware of many potential hazards.
This experience was a red flag. I realized that my trial and error approach was risky, and my safety depends on understanding and identifying hazards, and not counting on luck as a way to manage risk. I wanted to learn more about making aerial assessments so I could safely land in new territory. After years of practice, I’ve settled on the method below that can be modified as needed.
Aerial Strip Assessment
I organize aerial assessment into three categories: a high pass, a low pass, and the landing approach. Ground operations including rollout, taxiing, and takeoff are not considered here.
Checklist items will vary according to the location. For example, a glacier landing checklist will include items that don’t apply to gravel bars. An Alaska gravel bar checklist may not include hazards like powerlines, boats, people, and other aircraft, which are greater factors in the Lower 48.
I only include checklist items that I think are relevant to the mission. This eliminates nonessential tasks during critical phases of flight. During the landing approach, I want to be looking outside and focused on flying the airplane without distraction. If the lighting conditions aren’t good, if I’m not flying as well as I should be, or if I feel uncomfortable after making several passes, I probably won’t land.
Alaska Gravel Bar Checklist
Here’s an example of my Alaska gravel bar checklist for aerial assessment.
I take my time to look for things that are not obvious when evaluating a new spot. I fly at an altitude above tree and terrain obstacles to get a safer first look than would be possible if flying low-level. If outstanding challenges or hazards exist (unfamiliar territory, short landing area, confined area) I always make a careful assessment before attempting to land. The flyover pattern depends on terrain and conditions, but I don’t circle overhead.
There are times when I can determine whether or not a place is safe to land without a lengthy evaluation. Sometimes a single overhead pass will lead to pattern entry and landing with a continuous assessment to touch down.
The purpose of the high pass is to:
- Assess hazards
- Identify the landing area and the touchdown point
- Assess surface conditions
- Check the wind
- Make a pattern plan
- Verify a safe approach/departure before making a low pass
If things look good during the high pass, and I want to see more, I’ll fly one or more low passes. Low passes may be flown offset to the landing area, or directly over the landing area and close to the ground. Decisions like this are made on-site depending on the situation. I won’t drag a strip unless I suspect soft surface conditions or I am ski flying.
Low passes enable me to:
- Get a closer look at the details
- Verify a safe approach/departure
- Make an abort plan, check wind conditions, assess surface conditions
- Identify a touchdown spot
- Measure the usable length of the strip or landing area.
Bush approaches may involve nonstandard patterns and altitudes, and slow, maneuvering flight in confined areas. Forget standard patterns and fly a safe pattern that is responsive to the terrain and the conditions. I continue assessing during the landing approach all the way to the touchdown. If I attempt to land, I first identify the touchdown spot and the abort point before flying the approach.
My flow for a power-on approach in a Super Cub is:
- Fuel – both or fullest tank
- Carb heat – off on final
- Eyes outside
- Touchdown spot visible
- Aligned and tracking straight
If something doesn’t seem right, I immediately abort – the landing approach is a time for anticipation and decisiveness. Maintaining minimum controllable airspeed (Vmc), staying on glideslope, and spot landing precision is paramount for short strips. Don’t be careless and land short. I consider this something that should be emphasized during training. If you are unable to touch down at or slightly beyond your intended spot, go around. (This may not apply to one-way strips with no go-around or when landing short is known to be safe)
Airstrip Measuring Chart
I also developed an airstrip measuring chart that is printed on the back of the gravel bar checklist. After a low pass at measuring speed, I can quickly determine the airstrip length using this chart. I use GPS ground speed, not indicated airspeed when measuring. I like to count or use a smartphone to record the number of seconds it takes to fly over the usable portion of the strip. The ideal measuring speed will be influenced by the type of airplane, weight, wind, and terrain. I typically fly a 60-mph measuring speed in a Super Cub. Accurate measurements require a level flight path and consistent airspeed.
I keep this chart and the Gravel Bar Checklist handy in the plane. If you’d like to print yourself a copy, a PDF is available for purchase in the Tundra Pilot store. I recommend printing it double-sided on high-quality paper, then laminating it.
I’ve learned a lot about strip assessment since my first bush landing, but I know there’s much more to consider. What is your method?