Grass Runways Archives - Golf Hotel Whiskey

How to transition an aircraft between grass and pavement

Sylvia, the blogger behind the Fear of Landing blog, recently had an unfortunate incident where her aircraft got stuck in the mud on a grass runway alongside the taxiway – something that reminded us of an old query on Ask Flight Instructor about how to transition an aircraft from grass to pavement and vice versa. First, here is what happened to Sylvia:

When I went to turn back onto the taxiway I realised I hadn’t left myself any room to make the turn, I was going to have to enter the grass runway which ran alongside the taxiway. But in that case, I thought, why not just cross the grass and head directly to the asphalt. The radio was silent, no one was coming in, it wasn’t like I was going to be causing any inconvenience.

That turned out to be a bad move due to all the rain the airport had during the previous week and led to the following problem:

Luckily, Sylvia had help readily available who got her plane out of the mud (Warning: Any “handy loop” that is used for tying the plane down may not be intended to be used to tow it according to your aircraft’s handbook).

As for the old Ask Flight Instructor query, Thomas Wester had posted:

What advice is there for transitioning between a paved runway and grass tiedown area (and vice versa)? There is material on taxiing on soft surfaces, but I have not found anything specific to going between hard and soft surfaces.

Bob Watson responded by writing that you need to “keep the nose up in both cases” because the soft surface will likely be slightly lower than the paved surface – meaning going from hard to soft will involve a nose dip and you will want to have “full back-elevator” while taking it slowly and gently to prevent dipping the prop into the dirt. When going from soft to hard, you want to keep full back-elevator and maybe “even give it a little power to get the nose up onto the pavement” (assuming you aren’t stuck in any mud). He also added:

Holding back elevator also helps reduce some of the bouncing, but, depending on the terrain and the airplane, you might need to moderate the back pressure to keep the tail from hitting.

Finally, someone named Brian wrote that you should not take the transition perpendicular, but instead go at a 45 degree angle and keep the yoke in your lap. He then added:

Check the area you plan on transitioning before doing so. A slow taxi past it will suffice, but walking it before hand, when possible, is always best.

In that way, you will avoid potentially embarrassing incidents involving mud.

Cows and aircraft don’t mix (especially on runways)

We have mentioned stories or incidents involving emus, dogs, rabbits, wild pigs, turtles, deer, a bull and even cat fish running, hopping or slithering across runways, but incidents involving cows seem to be greater than one might think.

For starters, in an August 2010 US National Transportation Safety Board (NTSB) accident report excerpted on General Aviation News, a Cessna 182 pilot in Del Rio (Texas) was attempting to land on a private dirt strip. However, he became distracted by a cow adjacent to and moving toward the runway (being Texas, the runway must have been on a big cattle ranch) – causing him not to notice that he was too low on the approach. The pilot touched down short of the runway by about 5 to 10 feet, struck some rocks on a rise in the terrain and flipped over. There were no injuries but the aircraft had substantial damaged.

Granted, that was in Texas. However, NYC Aviation reported early last year an incident at the Mayor Buenaventura Vivas Airport in Santo Domingo, Venezuela, where an Aserca Airlines McDonnell Douglas MD-82 struck two cows (who died instantly) because they did not move fast enough. The jet’s left main landing gear and left wing flaps were damaged enough to keep the aircraft grounded until repairs could be made.

NYC Aviation also mentioned that in 2005, a herd of cows were hit by an Air France Airbus A330 while landing in Port Harcourt, Nigeria. That led to local authorities arresting stray cows and holding them until their owners paid a fine. In addition and in 2011, an Aviastar Twin Otter hit three cows while landing at the Komodo Airport in Indonesia (at least they did not hit any Komodo Dragons!)

However and if you think cows only pose a threat to aircraft in Texas or in developing countries, a British biplane clipped one while making an emergency landing in a field that was caught on video back in 2008:

Luckily, neither the cow nor the aircraft were seriously injured and the pilot was glad to avoid hitting a fence that could have led to worst damage.

In other words, keep an eye out for any wayward cows when landing on runways – especially grass runways or fields.

Tips for landing on grass runways (from a bush pilot in Indonesia)

We have touched on soft field or grass runway landings in the past (see here and here), but Matt Dearden, the British pilot behind the Bush Flying Diaries, Indonesia blog, must deal with slippery and slopping grass or dirt landing strips on a daily basis. In a recent post, Matt made the observation that worst kinds of grass airstrip he encounters are the pure grass ones grown on soil/dirt because the locals tend to build them with a pronounced crown with a slope on either side along with a ditch to catch the water and any wayward aircraft – especially those with a tailwheel.

That means you must land in the middle of the airstrip (who’s condition is next to impossible to judge from the air) and Matt noted that the proper technique is something you have to judge depending on:

…. how fast you’re going, how much runway is left and how close to the edge you’re drifting. Braking the opposite wheel can help but if it’s really slippery you sometimes have no option but to add power and get some airflow over the tail to help pull the aircraft back to the centre.

Matt added that the fun continues even when you are at taxi speed because a fully laden Porter can weight is 2660kgs and its easy to get stuck in any mud if you don’t keep the aircraft moving while the hardest part will be making a 180 degree turn.

Likewise, getting ready for take off is also not easy – especially in a tailwheel and on a slope because you can get stuck just as easy while trying to maneuver or if you stop. Obviously there is a bush pilot trick to handle that, but Matt wrote:

It’s quite a curious feeling when all three wheels are sliding sideways and the only way to stop it is to add power and turn into the slide.

In other words and even if you aren’t taking off and landing on remote grass landing strips in the jungles of Papua, it might be worth it to check out Matt’s blog for tips about landing on grass runways in rainy Britain.

Landing on a wet grass runway proves fatal

General Aviation News will often reprint accident reports from the US National Transportation Safety Board (NTSB), including an October 2009 accident report that involved a Piper Archer in Oliver Springs, Tennessee.

According to the accident report, a pilot was attempting to land on a grass runway that was wet. When the Piper touched down on the runway, it bounced back into the air.

The Piper then touched down on the runway for a second time. However, the aircraft then turned about 45° to the left and skidded toward the woods bordering the runway. The aircraft crashed through a fence and hit a tree with the left side of the cockpit taking the full force of the impact – causing one fatal injury and three minor injuries.

To avoid having the same situation happen to you, check out a great article by William L. Gruber that’s posted in the Flight Training section of the AOPA’s website. Gruber noted that landing on a grass field takes extra care because they are constantly changing depending upon the season and the amount of recent rainfall in the area. He also noted that it will take much longer to get off the ground on a wet grass runway than on one that is dry.

In other words, be extra careful during any wet season and be sure to talk to pilots who have recently used the grass runways you intend to use.

How to make a soft field landing

Jason Schappert of MZeroA.com has recently put together a great short video about how to make a soft field landing (that is, a landing on an unpaved surface such as a grass or a dirt landing strip). In the video, Jason talks you through a proper soft field landing by first noting that you will want to protect your nose wheel. As he explained in the video:

I’m going to come in and you know what, sometimes I even carry a little bit of power because I wanna touch down on the mains first and really hold that nose wheel off until the last second. You also want to really avoid braking.

In addition, he noted that the key to a great soft field landing is to manage your airspeed. Hence, your speed will need to be a bit slower (however, this is not necessarily always the case with every soft field landing).

Jason’s short video is well worth watching, even if you do not regularly land on soft fields.

Take-offs and landings on grass or dirt runways

Taking off and landing on a grass or dirt runway is different from taking off or landing on a paved one. In fact and in most instances, larger planes weight too much and would sink under their own weight while the uneven nature of such runways could be potentially damaging to the plane and dangerous to all on board.

Hence and if you are a pilot who is not entirely comfortable with taking off or landing on grass or dirt runways, Vincent has posted an excellent entry on his Plastic Pilot blog with some handy tips. As he pointed out, take-offs from a grass or dirt runway need to be done under a very low speed followed by acceleration while approaches and landings require higher than usual nose-up attitude. In other words, some additional training would be required.

In addition, Vincent also pointed out:

Just like each pilot, I’ve my strengths and my weaknesses and I think it’s important to know them. I continue to extend my comfort zone, step by step. Sometimes with an instructor, sometimes alone on board.

Definitely good advice for anyone who is not yet comfortable with taking off or landing on a grass or dirt runway or for that matter, any other aspect about flying.