June 2005-
I was recently on a flight with a friend of mine in his light twin, and something occurred that made me realize I should have been more prepared.
While it’s certainly not possible to train yourself ahead of time for every type of failure, there are a number of things that can go wrong that would be far easier to handle if we gave it a little thought and worked out the details of what the most appropriate action might be.
The particular failure that got me thinking was simple enough: soon after takeoff my friend noticed that the right brake pedal on the pilot’s side went all the way to the floor without a hint of braking resistance in the line. He asked me to check the copilot’s side and, as expected, I verified that the wheel braking system on the aircraft’s right side was apparently out of fluid.
Sometimes, if the problem is more air-bubble than fluid-level related, pumping the pedal up and down a number of times will restore some level of wheel braking for some period of time. If that was the case, the drill would be to pump the brakes up on very short final so you’d have some braking on that side during rollout.
For us that day, that was not the case. The right pedal—both pilot and copilot—would push all the way to the floor as if there was nothing there at all, which was exactly the case.
As we suspected at the time and verified later, there was a small leak in the brake line to the right main wheel and, over time, the hydraulic fluid that operated that wheel brake had vented itself overboard. So, here we were with only left side braking remaining. That brought up some interesting en route questions, and all of them should have been easily answerable from our own experiences in this and/or other comparable light twins.
While I had some gut feelings about what we were about to see, I chided myself for not having experienced and practiced something like this before – especially since it would be so easy to do, and interesting, too.
Ask yourself these questions about the particular airplane you operate the most: how controllable on rollout will your machine be if you only operate the wheel braking on one side? Can the pulling moment on the braking side be overcome by the friction of the nose steering tire on the pavement? Can you utilize any level of braking force at all on the remaining side, or will the directional control problems be too great for even a mild stab at the remaining wheel brake?
Tailwheel pilots can probably get away with far less one-wheel braking than pilots who have a nosegear to help absorb the directional miscues.
Finally, ask yourself how much runway will it take for your airplane to come to a complete stop if you don’t (or you can’t) use any wheel braking whatsoever? If you can’t answer these questions, take your airplane up on a practice flight so it can provide you with the correct answers.
The most important piece of data for a pilot to gather first is about the worst possible scenario: complete braking failure. How much runway will it take for your airplane to come to a stop with you utilizing no wheel braking at all? Take a guess, then go see; you might be surprised by the answer. The variables here are touchdown speed and touchdown point.
Using an approach speed that is a little lower than normal, but not uncomfortably so, get the airplane established on a long final approach (a longer rather than a shorter final approach gives you more time to have everything stabilized). Put the airspeed needle right on the target speed you’ve selected, and don’t allow it to vary.
Control rate of descent with the throttle and let the airplane settle as close to the end of the runway as you comfortably can without running the risk of landing short of the runway threshold.
Let the airplane flop onto the runway as soon as you pass the threshold, since it will slow down measurably faster while rolling on the pavement rather than floating a few feet or a few inches above it. Leave the flaps down (full landing flaps are the obvious choice for this situation) since flap drag will also help to dissipate the landing airspeed’s energy.
On many airplanes, adding more and more up elevator control as the airplane slows (but not until airspeed is less than flying speed; you don’t want to pull the airplane into the air again!) will help with the deceleration process.
As you can see, all of this is easily practiced on any day that you care to. Try doing it on a calm wind day to get an accurate readout of how much distance it actually takes to stop a brakeless airplane. Also keep in mind that at higher-elevation airports or on higher density altitude days, it will take somewhat more rollout distance than sea level/standard conditions would because the true airspeed will be higher for a given indicated airspeed at the moment of touchdown.
Now, go back and do exactly the same drill using the wheel brakes on only one side. The initial part of the landing with one brake is exactly as it would be with no braking – that is, a long, stabilized final approach with airspeed at a low but comfortable setting and the touchdown target as near to the threshold as practical.
Since the airplane will be pulled in a the direction of the applied brake (for example, if you are landing with only the left wheel brake working, the airplane will want to head for the left edge of the runway), make the touchdown as far to the right as is reasonable considering the runway’s width so that you have more room to sashay over that way without leaving the designated landing area.
At the first hint of directional control problems during a one-brake landing, totally let go of the braking effort on the good side so that the airplane will be completely steerable again. It is far more prudent to go off the far end of the runway at 20 knots than to go off the side and into the trees and buildings at 50. Still, most light airplanes will tolerate some level of one-sided braking (slow and easy is the braking byword here) while keeping directional control between the metaphorical uprights.
So, how did it work out for us that day? My friend turned a two mile final approach, then pegged his twin’s airspeed about 10 knots lower than usual—just a little below the blueline airspeed. He let the airplane touch down on the right side of the centerline within a couple hundred feet of the threshold end.
Once firmly on the ground, he slowly added just a hint of left braking while keeping the engine rpm slightly higher on the left side to assist the nose steering in tracking us straight and true down the blacktop. I was sitting in the copilot’s seat and, since what we were looking for was as much drag as possible on the aircraft’s right side to make up for the lack of drag from a right wheel brake, I pushed the aircraft’s entrance door wide open into the landing breeze. With the door opened on the right and just the slightest touch of wheel braking on the left (hardly any at all, he was to tell me later), his twin came to a standstill in less than 2,000 feet.
Since the runway was 4,000 feet long (and with a sandy overrun area beyond it), the entire operation had been conducted with lots of fudge factor. Knowing ahead of time approximately how much runway a brakeless landing will take is an interesting number that can be discovered in an interesting personal training session.
It’s a nice thing to do periodically with your airplane, and you might find that you aren’t quite as dependent on one of your airplane’s systems as you might have thought that you were. This way, if both brake pedals were to go straight to the floorboards someday, you can turn to your passengers and announce, “This is no problem… it only takes blank feet for this airplane to stop with no wheel braking at all.” Just remember, though, that you’re the one who needs to accurately fill in that blank.
Editor-at-large Thomas Block has flown nearly 30,000 hours since his first hour of dual in 1959. In addition to his 36-year career as a US Airways pilot, he has been an aviation magazine writer since 1969, a best-selling novelist. He owns an L-19 Birddog, which he contends is a straight cross between a Piper Super Cub and a high-wing Cessna taildragger.
