What is arguably the most abused, mismanaged, forgotten, diminished yet important part of your King Air?
It’s not the potty knife, not the copilot control yoke and not the baggage compartment floor. All of those are important – and almost certainly shoved aside in importance – but they do not win such inglorious distinction as being the most abused, mismanaged, forgotten, diminished and important part of your King Air.
The nose gear tire earns that title and is the unsung hero of your King Air.
The nose gear tire takes an immense amount of abuse, holds up an enormous amount of weight, accepts huge side loads and does it without hardly complaining. The nose tire on your King Air takes a licking and keeps on ticking, usually. We rarely have trouble with the nose gear tire, but when it does fail, it fails with flair.
Think of whatever automobile you presently drive. The front tires on most land vehicles do the steering, and most vehicles have two wide front tires to accept the side loads, grip the road and handle the bumps. Your airplane has one tire that is half the size of an automobile tire. Wise owners rotate the tires on their automobile to equalize the torture the front tires experience. The automobile front tires are immensely more capable at handling abuse than an airplane nose tire, but your automobile does not have to fly. It is built with strength limitations that an airplane engineer can only dream of enjoying because of inherent weight limitations in aviation. In an airplane, the nose wheel not only has to hold up immense weight and withstand tremendous side loads, but it also must retract into the wheel well and be lightweight. It is an engineering marvel.
At the business end of that marvel is the nose tire, literally “where the rubber hits the road.” This tire is also a technical wonder. That one single tire is required to go from not turning at all to turning over 100 KTAS in literal seconds (on landing), handling the side loads imposed from a pilot (properly) yawing the tire into the wind, enduring the brutal cold temperatures and ridiculously low pressures at high altitude and steering a huge vehicle with a high center of gravity. The nose wheel on a King Air takes an enormous amount of abuse in daily life and even more abuse with a rookie at the controls. And it handles this abuse with aplomb – until it doesn’t. That’s when your life takes a turn for the worse.
Where’s Murphy?
When the nose tire fails, it fails completely – rolling off the rim or deflating. In either scenario, you’ll have no steering. Wherever you are, that’s where you’ll be until expensive non-scheduled maintenance can occur. With a nose tire failure, you can bet that Murphy is hanging around nearby. Usually Murphy lives at away-from-home airports that don’t have an adequate maintenance facility. Whether the failure happens in a hangar, on a ramp or on the runway, that’s where your Murphy-infested troubles will start. It usually happens when the airplane is full of fuel, full of passengers and empty of options.
But changing a tire at an outlier airport is chump change compared to the pain involved with a prop strike. It’s usually not a prop strike, but a dual prop strike. You’ll have entered the land of the ugh-known. A prop strike means the engines will come off the airplane, be sent to an engine shop and the expenses will skyrocket. One prop strike can cost hundreds of thousands of dollars, and if both props hit the ground, you can double the costs. Murphy will take over your bank account and create downtime havoc.
If you simply have a nose tire failure, the props will probably not strike. But, a nose tire usually fails because of some pilot-induced buffoonery, either a hard landing, improper flight control positioning, a short escapade off the pavement or poor aircraft management. When those events occur, a prop strike is a strong potential.
Think about the side loads
When you take off or land in your King Air, you usually contend with some sort of crosswind. That crosswind must be neutralized for the King Air to take off or land in a straight line. On takeoff, the crosswind must be countered and there is more surface area aft of the airplane’s center of gravity. So, the crosswind imposes a tremendous yawing effect on the airplane, even on the ground.
What counteracts this yawing effect? The friction between the nose wheel and the ground. In a similar situation, when landing with a crosswind, there are also side loads. While in the air, the pilot counteracts these side loads with a crab maneuver. During the landing flare, the pilot banks into the wind (the horizontal component of lift). Just after touchdown, there is the friction between the tires and the ground. These side loads are immense and must be overcome to ensure a safe landing. While on the ground, the nose tire becomes the pilot’s best friend.
Want proof? Try making a crosswind landing on a contaminated icy runway. When the nose wheel cannot make firm contact with the ground, the airplane will not be able to defeat the crosswind and the airplane will probably crash. Of course, I never want you to land your King Air on a contaminated runway with crosswinds. I hope my mere mentioning this scenario causes you to revolt against the potential. I just want you to sense appreciation for the work the nose tire is doing every day, and your innate understanding of landing on snow (or ice) gives a reference for the experience.
When you land in a crosswind, if you position the flight controls correctly, your nose tire will not be aligned with the runway centerline. If you land correctly, you’ll bank into the wind (landing the upwind main tire first and then land the downwind main tire), and you’ll have downwind pedal applied. When the nose tire touches, it will be pointing downwind. There is a bungee (shock absorber) in the nose wheel steering system that helps cushion the pilot’s feel of these side loads, but the side loads are felt completely by the nose tire. Instantly, your nose tire goes from not turning at all to turning almost a hundred miles per hour and accepting a huge side load. Landing is a torture chamber for your tires.
All these immense forces happen if you fly the airplane correctly. What happens if you don’t?
If you pilot the airplane incorrectly (are ham-fisted or ham-footed), the abuse on your nose tire can be exponentially greater than that of a normal landing. I think one of the worst parts of our training ecosystem is that many pilots never receive training in the real airplanes. Much of our training occurs in pathetic advanced aviation training devices (AATDs) that are not suitable (not approved) for training ground operations. We have a whole generation of pilots who have received minimalistic training landing a King Air. If you are one of these pilots, consider finding an insurance-approved training provider that does not have an AATD. Did I just hit a nerve? Good. I hope it causes you to rethink your training plan if you use an AATD trainer.
Just simply turning
The side loads can be immense just taxing a King Air, even at slow speeds. Because the airplane is multi-engine, a pilot can use asymmetrical power to assist with a turn. While this is an appropriate and good pilot technique, I see pilots often use too much power in turns, which creates side loads that your nose tire is not designed to withstand. Your nose tire can “roll off the rim” by making a tight turn and applying excessive power on the outside engine. While this operating practice will turn your King Air quickly, the side loads on the nose tire can be incredible, and this is a frequent fault with a rookie King Air pilot. Don’t be that rookie.
Give it some love
To give your nose tire a chance at handling these loads, you’ll want the maintenance on your landing gear system to be exemplary. Make sure your system has tight fittings and no excessive play. You can know how much play is in the system by feeling the control in your pedals while taxiing. Can you move the pedals when the airplane is static on the ground? If so, there’s slop. Many King Airs that come to our maintenance facility arrive with excessive play in the system, and inevitably the nose tire has excessive wear because of this slop in the system.
There is an argument to be made to have all your tires replaced at every phase inspection, regardless of apparent condition. Phase inspections happen every 12 months or every 200 hours in a King Air. If you fly more than 200 hours per year, you’ll want those new tires. And, if you fly less, won’t you feel good about having fresh rubber? The airplane will be placed on jacks at every phase inspection, and the cost of changing tires when the wheels are already removed is minimal.
A fault I see with King Air pilots is to “go cheap” in two areas of ownership: tires and batteries. These are two areas that can cost you greatly! An unplanned blown tire will destroy any savings sought through frugality. A weak battery can cause an expensive hot-start. In either case, if you have a worn tire or a weak battery, replace it. If you think, “I can get a few more landings out of that tire,” you are already far down the road to a very expensive event.
And tire pressure cannot be over-emphasized. This is the cheapest insurance policy you can purchase. You should check the tire pressures on all your King Air tires at least every two weeks. There’s zero excuse for not checking the nose tire; the valve stem is easily accessible and it’s an easy check. Make tire pressure checks a part of your routine.
Keeping your nose tire pressure at the proper level virtually ensures you’ll never roll a tire off the rim, as a properly inflated tire is extremely difficult to unseat. And a properly inflated tire resists bulging with side loads.
While I’m on my soapbox about tire pressure, I recommend you use pure nitrogen. You can purchase a nitrogen bottle for minimal money and one filling can last years. We keep our nitrogen bottle on the golf cart that we use to tug our King Air.
The next time you push or pull your King Air in or out of the hangar, look at the lowly nose tire. It needs some love and appreciation for the work it does! Just a little love and attention will ensure you are never standing next to your airplane with the previous passengers watching you make phone calls to far-away maintenance providers, trying to come up with a plan to fix your problems.
The nose tire truly is the most abused, mismanaged and forgotten part of your King Air. But now you know that it is also one of the most important parts of your King Air. Treat it with dignity and respect, give it some love (proper air pressure) and appreciate it for the work it delivers for you every day.