Gear-up Landings - Asphalt or Grass?

(To see a short clip of the T-28 landing gear-up, click here)

Here's one of those decisions I hope you never have to make

Let's say that the gear on your airplane won't extend. You've tried everything and nothing works. You've even tried the thing you do in your doctor's office during your medical exam: you jumped up and down on one foot for 20 seconds directly over the main gear attempting to dislodge the recalcitrant assembly (didn't know that was a standard in-flight maneuver, did you?). The gear won't extend and now you must land. Should you make the gear-up landing on the runway or on the grass (i.e. sod, dirt, etc.) next to the runway?

Here's the answer, short and sweet. Statistics suggest that putting the airplane on the asphalt is likely to cause less damage to you and your airplane than putting it on the grass.

Of course, whenever I ask pilots in a seminar about choosing between the grass and the asphalt, they're usually evenly split between the choices. Those choosing to land on the grass often do so because they fear a postcrash fire. In reality, a postcrash fire after a typical gear-up landing in a general aviation airplane is rare. In fact, it's extremely rare.

I say a "typical" gear-up landing because I'm not talking about the kind of accident resulting from a botched go around or other strange activity where the airplane slams into the ground with the gear tucked away in the belly. These events can rupture wing tanks (i.e. bladder, metal or wet wing types). I wouldn't begin to speculate about the potential for a postcrash fire under these circumstances.

Gear-up landings, however, are not physically traumatic events. They rattle the mind more than the body. In fact, pilots who've landed gear up sometimes have a hard time believing that they just did the dirty deed, though the sound of screeching metal on asphalt and the ineffectiveness of the brakes are a few of the early warning clues that a gear-up landing has just taken place.

While looking around quickly to try and see who else might have done such a thing, you can take some comfort in knowing that you're more likely to sustain a bruised ego than a bruised body from what is taking place. Bodily risk in these situations results mostly from fire, and for several reasons the odds are pretty good that there isn't going to be a fire.

How Not to Light Your Fire

To have a postcrash fire you must have three things: spark, fuel and oxygen.

Certainly there's enough oxygen in the air to start a fire during a gear-up landing (unless, of course, you're landing gear-up in Los Angeles during our annual carbon monoxide festival).

During most gear-up landings in metal airplanes, there's no lack of spark either. In some cases, you can almost provide your own night lighting for the runway by landing gear-up. Personally, I prefer to use the runway lights myself, but each to his/her own.

Oxygen and spark mean nothing if you don't have fuel to burn. Given a typical gear-up landing, it's unlikely that you'll damage, much less rupture, a fuel tank. And you're not going to grind through the metallic belly up into the tanks either. Look underneath an airplane that's landed gear-up and you'll find less belly damage than you might suspect. When metal contacts asphalt, it results in very little friction, which explains why airplanes landing all-gear-up slide hundreds of feet.

The FAA should be happy that airplanes don't have more powerful gear motors. Otherwise, a pilot might land gear-up, hit the switch, and pop right back up on the wheels. Sure, he'd have a slightly damaged airplane and funny looking propellers, but he wouldn't leave much evidence at the scene, would he?

To put it simply, NO FUEL, NO FIRE.

Sumps aren't Chumps

"Oh, wait," you say, "what about the sump drains in the wings?

OK. What about them?

Do these add to a chance of a postcrash fire? Hardly.

Considering that low wing airplanes have considerable dihedral (Figure 1), you're not even close to contacting a wing sump drain with the ground. The next time you're on the flight line, measure the height difference between a wing sump drain and the belly in a typical low wing airplane. It's often five, six or more inches above the belly base line in most airplanes (high wing airplanes, of course, have an even greater advantage here).

"OK," you say, "what about the belly drain?"

OK, what about it?

Granted, a few airplanes have drains under the belly. Most of the time, these are gascolator drains (a place where fuel can be filtered and tapped one last time before entering the fuel pump). Some airplanes with gascolator drains have ridges or structures on the belly that prevents the drains from making direct runway contact in a gear-up landing. Even if a belly drain is damaged and leaks fuel, it's doubtful that there will be enough liquid to cause an explosion. That having been said, it's still prudent to shut off the fuel before making an intentional gear-up landing.

The chance of a postcrash fire after a gear-up landing in these instances is so rare that I couldn't find a single occurrence as I searched the NTSB database for the last 10 years (remember, I'm talking about typical gear-up landings in small general aviation airplanes here).

Where There Are Gear-Up Statistics, There Is No Fire

I went to the NTSB site (http://www.ntsb.gov/Search/srch_ch.htm) and typed in gear-up landing. I received 271 reports, and there wasn't a single fatality resulting from a typical gear-up landing. In the majority of these cases, both pilot and passengers weren't even injured. Not all of these listings were pure gear-ups. In a few cases, a pilot crashed an airplane during a go-around after the gear was retracted. This resulted in a gear-up landing, but not the type we're discussing here. Such instances were rare, however.

Another Gear-Up Study

A previous study covered a three-year period and examined 329 gear-up landing accidents. Of these, 192 forgot to lower their gear (with most landing on hard surface runways) and 186 had mechanical problems (no data as to whether they landed on grass or asphalt). Only one fatality was reported in this study. It occurred when the pilot of a Beechcraft Baron executed a gear-up landing followed by a gear-up takeoff.

That's right, a gear-up takeoff. During the flare, with the gear tucked safely in the belly, the pilot heard the sound of two very expensive weed whackers (his props) taking chunks of asphalt out of the runway. He raised the nose, applied full power and attempted a go around. During climbout, an engine failed and an assortment of untamed aerodynamic forces drove the airplane into the ground. What a tragedy!

If you're interested in reading about two other accidents where pilots attempted to go around after a gear-up landing, try these two NTSB reports:

Here's my rule for gear-up takeoffs, which I unashamedly stole from the O.J. Simpson trial: If the prop tip hits, you have to commit. So don't think of going around once the prop tips strike the ground.

As you can see from these statistics, your typical gear-up landing isn't that dangerous and it's not likely to end in a postcrash fire.

Petrol Withdrawal

What about flying around until you consume most of the fuel before landing? Based on these statistics, that doesn't sound like a necessary thing to do, does it? After all, how much fun will you and the passengers have knowing that you'll eventually have to go back for a gear-up landing? I suspect you're better off spending your time trying to solve the gear problem instead of worrying about burning off fuel.

Foam Alone?

What about foaming the runway to prevent a postcrash fire? What fire? Again, the statistics don't indicate the likelihood of a postcrash fire. I think it would be fun to land in foam at least once (I suspect it's kinda like popping out of a really thick cloud). Other than for jollies, why waste your and other people's foam? Besides, I don't know of too many places that will foam runways for you. In fact, I don't know of any.

One of the things discovered many years ago was that pilots aren't always that good at hitting the foam during their gear-up landings. Sometimes they float over it as they attempt to make a smooth landing (remember, airplanes are more likely to float without the drag of extended gear).

What about having the fire trucks available for your gear-up landing? Of course!!! In fact, I'd be inclined to fly to an airport with these services and make my gear-up landing there. Yes, this would obviously be a bigger airport and I may inconvenience a few people. So what? It's my hide and I'm covering it in a conservative manner. You should consider doing the same with your hide and that of your passengers. Even though a postcrash fire is rare, it's still comforting to have those firemen chasing me down the runway with all those lights flashing and signals wailing. Besides, some of these firemen don't get to see much action. They like this stuff.

Grass at Last?

But why not land on the grass anyway? After all, it's softer isn't it, and less likely to cause less damage to the airplane? Not always.

While the grass may be softer, you must remember that the grass is connected to the ground. And ground is often hard and bumpy. You could land on the grass and have part of your airplane dig into the dirt. This jostles the airplane as well as its cockpit contents and may result in an unpredictable deceleration. In other words, instead of sliding as you would on asphalt, you might have the cowling, a wing or an unretracted gear door dig into the ground. This might cause the airplane to come to a sudden stop. Unfortunately, when that happens the occupants often keep going until they strike something solid, which is when injuries and deaths occur. If a wing digs into the ground, you're also talking about major airframe damage, though I'm far more concerned with bodily damage than I am dings to the wings.

Suppose a wing or cowling digs into the ground and the airplane flips over? What then? The last thing I want to do is to try to get out of an airplane (especially a low wing airplane) that's gone belly up. It's possible that egress might be impossible through crushed cabin doors. Yes, baggage doors are a good alternative for egress, but I much prefer going out the same way I came in, thank you.

Don't get me wrong. If the grass is thick, consistent and growing on level ground, landing shouldn't present a problem. Landing gear-up on the fairway of a golf course is a good example. Landing on the putting green is even better (this has to be a short field landing, of course). Whatever you do, don't land gear-up on a driving range. After years of trying to hit the guy in the protected ball-retrieving tractor, there's nothing a hormone-crazed teenage golfer would enjoy more than aiming at a new target!

Many years ago at Watsonville (CA) airport, during an airshow, a fellow in a Mooney turned downwind with his gear tucked away in the belly. He landed gear-up. Because of the strong crosswind (that he didn't correct for), he slid off the runway. The airplane flipped over, plowed through the dirt for 30 feet and churned up a mushroom shaped dirt cloud. As the air cleared, witnesses said they saw three gear pop out of the belly and point skyward. I guess some people will do anything to keep from looking bad. (I was told that the pilot exited through the rear baggage door.)

Come Out, Come Out, Wherever You Are

Now let's take our analysis a little further. Suppose only two gear came down while one refuses to budge? What now? Should you land with two extended and one retracted? Or should you retract the two gear and make a clean gear-up landing? Hmmm? Let's think about this. First, I'm assuming that you've done all that you can possibly do to solve the gear problem. This article isn't intended to cover these points.

Nose Job

Let's assume you've got the main gear extended but the nose gear isn't budging. My suggestion is to land with the main gear extended. Touch down on the mains, throttle back, and hold the nose off for as long as possible. Yes, you can shut off the engine to prevent sudden stoppage of the propeller. I say this with the caveat that it takes a little extra experience to execute a safe gear-up landing and fiddle with the mixture control at the same time. You be the judge. If you don't have the experience, then don't mess with shutting the engine down. The same goes for trying to level the prop by engaging the starter. If you feel comfortable doing so, then have at it. After all, you da' man (or wo-man). You decide. Over the years I've seen a few gear-up landings. In particular, I recall a Cessna 310 landing with the nose gear in the retracted position. No big deal. The pilot landed on the runway and did an outstanding job. I wondered how well things would have gone had he tried landing on the grass. I can just imagine the 310's nose digging into the dirt and flipping the airplane over. No bueno. Keep it on the runway unless you have a real strong reason for doing otherwise. Also keep in mind that your highest priority is the preservation of you and your passengers, not protection of the airplane's skin.

One Main is the Game

Suppose the nose gear and one main won't extend. This leaves you one main gear on which to land. It's probably best to retract the gear and make a clean all-gear-up landing. After all, this is no time to practice unicycling in an airplane.

When a Main on the Plane is Lame

What happens if the nose gear and one main gear extends but the other main gear won't? This is a little tougher to answer. I'm inclined to say that it's six of one, half a dozen of the other. There's really no hard evidence that landing in this configuration, as compared to an all-gear retracted landing, makes all that much difference. Landing with two gear down at least allows you to hold one wing up with aileron control before the wing eventually drops to the runway.

The most common reason that pilots choose to land this way is to avoid or at least minimize engine and prop damage. It is, of course, likely you'll cause less damage to the engine and prop on a single-engine airplane compared to a twin under these conditions.

Landing with the nose gear and a single main gear extended becomes troublesome if you have fuel tanks on the wing tips. The Cessna 310 is a good example. Its main tanks are on the wing tips. If one of these tanks ruptures during ground contact, that could be very bad news, though I know of no case where this has actually happened as a result of a gear-up landing.

Aside from saving the prop and preventing sudden engine stoppage, wing damage is an additional problem. While this isn't the kind of damage that typically ruptures an internal wing tank (I'm speaking of an inboard fuel tank here), it does bend metal, and that may result in extensive airframe repair (I mention this not for airplane repair considerations but because less damage to the airframe probably means less physical damage to you). A wing striking the ground may cause the airplane to twist, turn and otherwise keep from moving straight, as it usually does when making an all-gear-up landing. Does this mean the airplane is likely to flip over when one main gear is not extended? Nope. The evidence doesn't suggest that it will in a typical gear-up landing, but it does make the landing a little more unpredictable.

Were I in this situation with the nose gear and a single main extended, I'd remember that the statistics show no fatalities and very few minor injuries for a typical gear-up landing (which, by the way, includes all types of landing configurations). I'd retract the gear completely and belly-in the airplane. Why? I feel I'd have better control over the outcome than letting one wing contact the ground. I also feel that I'd minimize the chance (as little as it is in this conditions) of the airplane flipping over. I would attempt to pull the mixture after, and only after, I was in the flare and was assured the landing was guaranteed. Remember, it's very difficult to go around with the engine shut down. Once you pull that mixture you eliminate your go around options. Don't be so willing to give that option up so quickly.

What happens if you can retract the nose gear and one main gear but the faulty main gear remains partially extended? I can't see that this is all that big of a deal when landing on the runway. It certainly would be a bigger concern when landing on the grass since the partially extended main is likely to snag on the ground. This may cause a little extra damage to the airplane but, once again, the statistics don't show it to be a dangerous problem.

To Flap or Not to Flap?

Should you extend your flaps on landing? If it's a high wing airplane, then it's probably best to extend the flaps. Many high wing airplanes have Fowler-type flaps that leverage the last bit of lift out of the air. Low wing airplanes, on the other hand, may not have such effective flaps. In other words, extending them may not lower your stall speed all that much. Extending them may cause more damage than it's worth. Personally, I'd study my low wing airplane and compare the amount of damage that I'd do versus the gain I'd get in reduced stall speed. The T-28 shown in this article landed with its flaps extended (it has very effective flaps). Also, I'd consult a mechanic and see if there is any chance of a flap rod breaking and penetrating a fuel tank.

Please, No Heroes!

Finally, please, please, no heroics. Your objective in a gear-up landing is to cause no harm or injury to anyone. Save your heroics for helping the elderly during pitbull attacks and landing jetliners when the crew conks out because they ate the fish. The airplane is expendable. If you don't believe me, ask your insurance adjuster. He or she will tell you that they'd rather pay for bent metal than loss of life. It's simply irresponsible and immoral to do wacky things in an attempt to save an airplane.

I will never forget the time I saw the video of a man in a truck racing along the runway trying to physically dislodge a stuck gear while the airplane flew just feet above him. It's hard to believe that someone thinks so little of their life that they'd risk it for a piece of metal. I hope this person didn't get an award for doing such a risky thing. Perhaps he thought the idea was pretty cool at the time. I don't think he'll see it the same way as he gets a little older. If he does get any older, that is. That was a risk that I wouldn't recommend anyone taking just to save an airplane.

If you have to land gear-up, do it under the most favorable conditions you can muster. Find a nice long runway, with plenty of services (tower airport, fire trucks, crash crew, etc.). Don't do anything fancy and don't let ATC talk you into using a shorter runway. Yes, it happens. I know of several cases where they tried to do just that. Make sure you unlatch the door, turn off the master and shut off the fuel, before touchdown. Pull the mixtures in the flare if you can, but it's not imperative that you do so. As the airplane slides to a stop, point out to the passengers how pretty those sparks are.

Once down, get out! Yes, I know, I said there's little chance of a post-crash fire, and that's true. So what? Little chance doesn't mean no chance at all. Get away. It's foolish to stand near the airplane in this condition. Suppose there is a small fuel leak and some bystander decides to light up a Marlboro. Now he gets to lose all his facial hair as well as a lung.

A purposeful gear-up landing is one of our less risky activities in aviation. So you don't have to do anything spectacular to save yourself and the airplane. Just make a normal landing and consider the things I've mentioned. Nothing fancy. Put your earplugs in if you don't like the sound of screeching metal. Keep your sense of humor about the whole thing. You did your best to get the gear down and it didn't work. Time to skid and tell. And remember, there's nothing to fear, not even gear itself.