How you fly when no one is watching...
 

A recent accident has me reminding myself that in some cases, a pilot may become very carefree when flying in an environment where no one is watching. A prime example of this is low flying over water, particularly in seaplanes.

Indeed, I happened across an aircraft manufacture's web page which describes low flying techniques in their aircraft. This page is still there, after their chief test pilot died in a low flying accident in one of their aircraft.

Canada offers magnificent expanses over which one could fly at any altitude, and no one would know, nor care. As a very new pilot, I recall low flying a frozen lake in a friend's 182. I was miles from anyone, who would know? Well, who would know if I CFIT'd it either!? I recall suddenly realizing, that over the unbroken snow, I had no idea if I was 50 feet or 50 inches above the surface - I pulled up, and never did that again!

Civil land pilots are not trained to consider the additional factors associated with low flying: Loss of vertical reference, wires, birdstrike, where you're going if it quits, and even loss of horizontal reference if you're low flying among higher ground.

I doubt that anyone (other than maybe crop duster pilots) would want the liability of conducting low flying instruction. There are small elements of it in a seaplane rating (glassy water landings), but otherwise everyone who could be liable, is probably more happy if you're at 500 feet, other than departure and arrival.

There is a very old quotation " there are old pilots and there are bold pilots, but there are no old bold pilots!"
Usually flying low you will have height references, trees, buildings, people etc, snow or water being the most likely exception but that is not the biggest risk. Far more pilots are caught out by low cloud, pressing on in worsening conditions, flying towards rising ground, between hills and unfamiliar mountains.

My advice to new pilots is fly solo in good weather where visibility is good, learn to recognise ground features and navigate without GPS, yes, actually use a compass, away from your airfield circuit stay over 1000ft AGL. In poor weather take an instructor with you, if he is any good he will teach you the safe limits and probably scare you ****less in the process. Apart from flying skills be meticulous preparing your aircraft, if the engine stops you are going to crash, only the lucky guys walk away.

No matter what how one has been trained, I recall one fatal accident involving (IIRC) an RAF Jaguar. It was theorised that the pilot was taking his height reference from what he thought were fully grown pine trees - in fact he was over an area of newly planted fir tree saplings, only a couple of feet high.

I also recall the story of another military jet pilot who suddenly realised the "sheep" he had been flying over at very low altitude were in fact white mushrooms.....

Floatplane training ... scraping across a ridge at treetop height to get to a different lake, to give the poor buggers living along the shore of the first lake a rest ...

"Don't you have any low flying rules here?"

"Yes, but with the usual exemptions for take-off and landing in accordance with normal aviation practice. And we're going to be landing ... ... ... somewhere, eventually ... ... ... in accordance with normal Canadian bush pilot aviation practice. Anyway I get a nosebleed any higher than this."

Temptation to show off....
 

How you fly when nobody is watching? no point in showing off then....

Delta Sierra, good advice, except for that last sentence! "if the engine stops you are going to crash, only the lucky guys walk away."

And you recommend that early solo pilots maintain a minimum of 1,000 AGL.
Even in a cranky old Cessna, you still have time from that height to aim for a field, a quiet road, a group of friendly trees (plan to end up on the higher branches), a factory roof, a parking lot...

Gliders descend more slowly, so have more time to make a choice. But power pilots get into more trouble by trying to turn back to the airfield from a low level failure, and spin while turning too slowly, which hurts. The most dangerous temptation is intermittent failure...I think I would say to myself "this aircraft now belongs to the insurance company!" and land ahead.

Amazing landings have had a happy ending, when the cranky old Cessna is UNDER CONTROL! the approach is made to the best choice at the slowest sensible speed.

At Booker, a power pilot passed out turning base, and ended up on a roof. But little damage, and no injury.

So my advice is to think ahead about what you would do in case the engine plays up or quits. Fly with an instructor or a friend, and practice choosing possible landing places. Glider pilots do this exercise in a motor glider before being sent solo.

In the UK it is perfectly legal to fly as low as you wish as long as you maintain the required 500ft separation from any "person, vessel, vehicle or structure".

I sometimes do low flying in Brecon Beacons, but I use tricks which help me judging my height with great precision (using my shadow on the ground, etc.) and I still add a huge safety margin to it. I think the question should not be whether you do it or not, but how serious you are about doing it safely.

And where I fly gliders we are taught to start picking fields from 2,000' agl. 1,000' in a Cessna doesn't bear thinking about IMHO

Horizontal reference
 

Is this a widely known phenomenon in aviation circles?

I have been looking at the Icon A5 incidents that Pilot DAR is apparently alluding to and have just checked that "horizontal reference" is not mentioned in the NTSB report into the May 2017 crash.

Loss of Horizontal Reference among rising ground (perhaps as the aircraft turned towards it) does seem a viable explanation for the excessive AoA applied before the apparent stall and loss of altitude to the ground. The aircraft was heading up a valley and then began a U-turn. As the closer valley side came into view ahead it may have created a rising apparent horizon and an illusion of pitching down.

The NTSB seem to be of the view that once in the canyon all hope was lost and the exact detail of the crash may not be important to them. Indeed the word "stall" does not appear in the report however the AoA increases to 17% and then decreases sharply with rising airspeed. I was just puzzled as to the mechanism that caused this experienced pilot to lose control in this way.


Report:-
https://app.ntsb.gov/pdfgenerator/Re...Final&IType=FA

Electronic devices report (includes flight path diagrams and FDR traces).
https://dms.ntsb.gov/pubdms/search/d...163&mkey=95127

Link to Docket (except report!?)
https://dms.ntsb.gov/pubdms/search/d...cfm?mKey=95127

Pprune thread
http://www.pprune.org/private-flying...ml#post9858555

During my training, I did a low level navex from Perth to Montrose at about 800 feet. My instructor was sitting beside me. It went very well but I was conscious all the time that I was traveling at 100 knots pretty close to the ground. The good thing in that area is that, even at that height there are plenty of fields to land in strait ahead. Just have to watch out for the wind turbines.

Being a flatland pilot, I was unaccustomed to the very different cues which one could experience in mountains or canyons. When I had to send another flatland pilot on a contract in the Canadian Rocky Mountains, I insisted that he take a "mountain course" so he would enter the program with the necessary tools. My attempt was a miss - he died in a crash when he took the multi million dollar modified Cessna 207 for an unauthorized tour in a canyon. Indeed, he did have lots of room to maneuver, it was not tight. However, he lost reference, and crashed into a slope. The accident was intensely investigated, but little more detail was ever revealed, he just lost his sense of up. I did not understand, it was a perfect flying day, the sky and horizon were easy to see.

It was a few years later that I was taking training in a helicopter in a mountainous area not far away. We were about 3000' below the crest of the mountain ridge, and my instructor told me to "toe in" to the surface of the slope. This means flying the helicopter gently so the toes of the skids contact the slope firmly, and holding a hover there. I found this really difficult, because as I approached the slope, my instincts were to pull up, which in the hovering helicopter translates to backward. The only way I could mentally overcome this was to reference the small trees I saw, trees always point up. With that, I toed in, and sat hovering there, with the rotor disc whisping some grass.

As I perceived my environment, knowing that even toed in, I was still flying, I realized that my horizontal reference was 40 degrees up, 3000 feet away. That would at best be confusing, at worst useless as a reference while flying fixed wing in there. With a blur of green and rock, not perceiving any tree tops nor horizon, horizontal reference is lost. At that moment, I knew how my pilot had crashed in the canyon, he turned, saw only green and rock, with no horizon, and lost it.

I teach this now, very carefully!

My first experience of flying somewhere non-flat was on Vancouver Island. Flying towards a sloping horizon was a new one on me, and I was having some difficulty even flying straight and level.

However the explanation came when the instructor, observing that I was confused, said "yes, this one has never been quite the same since the accident".

As the old song says, "It's not what you do, it's the way that you do it".