Tuesday, February 20, 2007

Visualizing a Different Plane

My instructor candidate had demonstrated a few spin entries when it happened: His window popped open unexpectedly. We thought it was a benign fluke, but it happened again. After the third unexpected opening, the window became difficult to keep closed. I flew the plane for a bit while he fiddled with the latch. The sudden rush of air and noise when the window opened was annoying, but I started asking myself "What's the worst that could happen?"

It's been said that good pilots are pessimists: They don't assume everything will be okay. Instead, they look for potential problems, holes in their own theories. I think good pilots are also able to simultaneously hold conflicting theories in their head. All of this leads a good, safe pilot to make conservative decisions and to imagine worst-case scenarios.

Each time the window popped open we were climbing back to altitude for the next spin entry. I figured the window opening unexpectedly during the descent portion of the spin recovery would be the worst. I had visions of the rickety window hinge and stay arm being ripped loose, the detached window traveling backward and hitting an important part of the plane, perhaps a control surface. That would be bad. So what were the options?

I thought about demonstrating a spin recovery technique for this particular plane that allows you to keep the airspeed within the greed arc during the recovery, but decided against it. My instructor candidate was now having to hold the window shut with one hand and that made it pretty difficult to fly the plane and talk on the radio. So we headed back to the airport. Once on the ground, he discovered a simple way to fix the latch. I think we both felt regret and I wondered if I'd made the best decision.

A few days later, I happened to read about an instrument rating candidate and an instructor in Florida who flew into some heavy weather. They had asked ATC if the radar showed any cell of precipitation and ATC had said "no." But soon they found themselves in heavy rain with lots of turbulence. The turbulence became so bad that one of the cockpit doors came out of its hinges. In the process, the cabin window popped open, was ripped loose, and struck the horizontal stabilizer on its way into oblivion. The aircraft landed safely and during the post-flight inspection the pilots discovered that the free-wheeling window had struck and bent the horizontal stabilizer downward about 30 degrees.

Less than two weeks after doing spins with the above-mentioned instructor candidate, I found myself with another instructor candidate in the same plane, making our way to the same practice area to do spin training. The spins were going to be a bit of a formality since this candidate, until about six months ago, had been flying F14s for the Navy. Here was a pilot who had flown 1.4 times the speed of sound, flown 500 feet over deserts and mountains at high speed, and performed countless carrier landings. Spin entry and recovery were not the issue. The task at hand was learning techniques for teaching GA pilots about spins while flying a small airplane.

I demonstrated an intentional spin entry and recovery first to the right, then to the left. This candidate learned very quickly and judging by the look on his face, this was the most fun he'd had in over a dozen hours of flight and ground instruction with me. I think he was happy to finally be pulling 2 or 3 Gs, even if for just a few seconds. For my part, I like to see people I instruct feeling happy. I also like it when the window stays shut.


Eric Gideon said...

Your very valid points about decisionmaking aside, I have to agree that spins were the most fun I had throughout my entire CFI training. Entry in a Super Decathlon is so fast - way faster than books or films suggest - and it just sticks a big grin on my face.

Too bad spinning our Yankee is verboten, but then again, just doing turns around the pattern in it is a lot of fun.

Anonymous said...

John -- will you consider writing more about that F-14 pilot who you're currently teaching how to fly in a small plane? You also had a great similar post about teaching an airline pilot back in your "Freight Dog Tales" blog. These are interesting stories. Thanks for your blog.

john said...

Did you think about the window popping open because the structure was deforming?
I personally have done spins in J3, Champs and Stearman. they're fun.

Jack said...

Interesting read John. I've only had one piece of an airplane depart the airframe (oil door on my Arrow). Ah, that gives me an idea for a new post. Still, the thought of anything leaving the airframe unexpectedly is something to take very seriously. Good call on getting the window latch fixed first.

zb said...

As a former design engineer, you might really find strong parallels to your current job... I don't know if you have designed software that had the purpose of making things fail-safe, but as a power-supply designer, it is my job to ensure the safety of my company's customers. So this is the parallel:

Whenever we get to gether to discuss possible bugs, there's
-the probability of the failure
-the consequences and
-our chance to find the flaw in our tests before we ship the unit.

As I have done a bunch of these meetings in the past couple of days, I do enjoy using your aircraft window as an example:
-Probability: 10 (out of 10), because it kept happening over and over.
-Consequences: 10 (out of 10), because it might hit something important.
-Find the flaw: 7 (out of 10), because at least while in the air, you couldn't really easily fix it.

Multiply, and you get 700. Everything above 500 is considered very severy.

It's a stupid formality (try to google "FMEA"), but it helps. Put simple: It is a pain in the a'' if you have to divert or return early, but if it might turn out to be really bad, there's no other chance.

If a company wants to save some cents on a certain product, they should only do this if it doesn't impair their customers' safety or leads to a possible and very expensive product recall from the field... The more severy the consequence, the easier the decision should be. That's why so much money is spent on redundant systems in planes or nuclear power plants.

To be less technical and more philosophical: I think that no pilot or engineer would be as stupid as a governor or politician who says that that atomic energy is absolutely safe, becuase these technical people just know that sh't does and will happen. As soon as you take the responsibilty and admit that nothing is 100% safe, you start improving safety.

Your story is a great example for this.

John said...

Thanks for your comment. I like the idea of doing the three phase risk assessment. I'd not heard of that particular approach before and hope that this sort of approach finds its way into aeronautical decision making.