Cohabitation of Gliders & Powered Aircraft

by Woody Minar

When you’re flying to another airport, how do you know if it’s also a “glider port” – an airport where gliders are present? And if you do know it’s a glider port, is there anything special you should know?

The first question is easy to answer – look on the sectional for a symbol of a glider with the letter “G.” But that’s not always shown; the Airport Facility Directory (A/FD) and other documents, in print and online, provide information, too. At the Osceola, Wisconsin airport (KOEO) where I am a flight instructor, there’s a glider symbol and we have an announcement on our AWOS: “Please be aware of glider activity in the vicinity of the airport,” during our soaring season to alert pilots of our activities.

Safety is paramount and practiced religiously every soaring day. A lot of things can go wrong. There is one exception: once the glider is released from tow, the pilot doesn’t have to worry about an engine failure, but he does have to be conscious of his altitude, gliding distance from the airport, and other gliders and powered aircraft. The second question will require a few more paragraphs.

First, there are four types of glider launches: self, winch, auto, and aero-tow. The self launch is a glider (called “motor glider”) that has an engine powerful and light enough to launch the glider into flight, then can retract inside the empennage or nose, or can be fully feathered when it’s time to convert to soaring. The beauty of this aircraft is that it normally does not require assistance from a ground crew and the engine can be restarted in flight. The winch launch uses a high-powered winch with a mile-long cable to launch the glider. The auto launch is similar to the winch, except it uses an automobile to launch the glider quickly into the air. Then there’s the aero-tow launch, which uses a tow plane, with a 200-foot nylon rope, to tow the glider to a pre-arranged altitude before it is released.

That’s pretty straightforward. The focus below will be on aero-tow launches, but similar procedures and problems at airports exist for all launches. So, what uncommon procedures should you be watching for near the glider port?

For example, a tow plane can have an engine failure on takeoff or the rope can break. Both are emergencies and fortunately, both the tow plane and the glider have the capability to release from the tow. The worst emergency is when neither can release.

Our safety briefing immediately before launch is this: If the emergency occurs within 200 feet above ground level (AGL), the glider pilot will land straight ahead or within a short turning radius. Between 200 and 500 feet AGL, the glider pilot will turn towards the direction of the crosswind and head back to and attempt to land on the takeoff runway or another runway if one is available and is the better option. You can imagine what would happen if a powered aircraft was taking off soon after the tow plane and glider took off and before they turned onto crosswind – and now here’s a glider coming back at you! Above 500 feet AGL, the glider pilot will do a modified pattern and land on the same runway from which it took off.

At Osceola, a busy non-towered airport, we are fortunate to have the Red Wing Soaring Association cohabitating very well with powered aircraft. We are also fortunate to have a large grass area south of Runway 10-28 to allow takeoffs and landings without disrupting operations on Runway 10-28. However, the asphalt and grass are not parallel runways, regardless of how far away the gliders are operating on the grass. Technically, and for safety reasons, this must be considered one runway. Treating them as parallel runways is a recipe for disaster should the glider or powered aircraft have an emergency and both are in operation on the same “runway.”

Aero-tow launches are similar to a normal powered aircraft takeoff except that the climb gradient is only about 300 feet per minute. As for auto-tow and winch launches, gliders pop up to pattern altitude very quickly. A powered pilot coming into the pattern where this type of launch is being conducted will certainly be startled to see a glider pop up into view.

It takes quite a bit of personnel and equipment coordination and movement to move a just-landed glider away from the runway, and ready that one or another glider for launch. As a result, golf carts and people will be moving about the area. The policy is not to launch a glider until a powered aircraft has reached its crosswind turn. A powered pilot should not take off when a glider is staged for takeoff near the asphalt runway, has just taken off, or is still climbing straight out. The tow plane and the glider have “ownership” of the runway until it makes its turn, just like any other aircraft.

What uncommon procedures should you be watching for at altitude in the vicinity of the glider port?

Aero-tow releases are usually 3,000 or 4,000 feet AGL on the upwind side of the airport. Gliders sometimes release at pattern altitude or lower altitudes during training to simulate emergencies. When releasing, the glider turns 90 degrees right and the tow plane turns 90 degrees left and dives, thereby providing 180 degrees and altitude separation.

Often, multiple gliders will share the same thermal; when they do, they will be turning the same direction. If they’re lucky enough to have a hawk or an eagle in the same thermal, all will be circling (thermalling) in the same direction. In between thermals, gliders will be flying on a straight heading searching for another thermal to gain more altitude.

Not all glider pilots are thermalling in the vicinity of a glider port; some seek to soar long distances cross-country. Now, that’s a challenge!

Minnesota Aviation Hall Fame member, Brian Utley, set the Minnesota glider “free distance” record of about 435 statute miles on May 31, 1975. Brian’s flight took him from Sleepy Eye, Minnesota to near St. Louis, Missouri. The longest free distance flight made from Stanton, Minnesota – the home of the Minnesota Soaring Club – was made by Jim Hard (a former Red Wing Soaring Association member) on April 6, 1990 when he soared to near Lafayette, Indiana, a distance of about 414 statute miles. In Wisconsin, the longest free distance glider flight was made by Christopher Prince, also a Red Wing Soaring Association member, on July 13, 2008 with a flight from Osceola, Wisconsin to Sandwich, Illinois – a distance of about 328 statute miles. The world altitude record in a glider is nearly 51,000 feet.

To achieve these feats, unstable weather with many cumulus clouds for creating lift, favorable winds for the “push,” a high-performance glider, and excellent pilot techniques are needed. The cross-country glider pilot will release at altitude, glide while trying to lose as little altitude as possible, thermal to regain altitude, glide, and repeat the process over and over until the glider pilot loses all lift and lands in a field if there is no airport nearby.

During these cross-country flights, the glider pilot is usually communicating his position on a unique glider-to-ground frequency with a ground crew that is trying to keep up with a trailer in tow and to find and assist the glider pilot with the glider disassembly and the return trip home after the glider eventually lands.

What are the right-of-way rules?

We all know that “Any aircraft in distress has the right-of-way over all other aircraft.” Lesser known is that a glider has the right-of-way over an airship, powered parachute, weight-shift control aircraft, airplane, or rotorcraft. Aircraft towing other aircraft have the right-of-way over all other engine-driven aircraft.

Our best soaring weather is when the atmosphere is unstable, there’s a larger than normal temperature lapse rate, cumulus clouds are crisp and well defined, and there is good visibility. The best lift is usually found in the spring and fall and over black fields, gravel pits, large concrete masses (industrial parks, schools, cities). You will not, however, find a glider thermalling over a large lake.

When thermalling, gliders will normally be seen circling over the same area for quite a long time trying to maintain or increase altitude. Glider pilots are taught to keep their head on a swivel because this is the best time for a mid-air collision to occur not only with powered aircraft, but also with other gliders. Powered aircraft pilots are trained and conditioned to look for aircraft traveling in one direction and may be startled to see a glider thermalling into their path.

Most gliders have radios powered by a small, lightweight battery; some gliders have handheld radios. Generally, they are inexpensive so they don’t offer the greatest audio quality (transmit or receive) or battery longevity. However, many gliders do not have radios. Remember, a radio is not required in a VFR aircraft – see and avoid rules apply. While every attempt is made to answer powered aircraft radio calls or to frequently radio position reports to alert other aircraft in the vicinity, this is not always the case. In the interest of safety, a glider club’s ground control position (field operation officer) will oftentimes help coordinate glider positions with powered aircraft. However, it is not uncommon to have gliders thermalling in the vicinity of the airport long after ground support people have gone home late in the day.

Furthermore, because of weight and power restrictions, gliders normally do not have transponders. This can become a problem with faster aircraft with TCAS (Terrain and Collision Avoidance System) on board. Again, see and avoid is essential!

Gliders use energy management to stay aloft and glide for long distances. A glider pilot, who wishes to venture away from their home airport and return, must be aware of the winds, their altitude, and the decay of thermals. Obviously, the further the distance, the higher the altitude that is necessary to return to the airport. Low-performance gliders have a glide ratio of 20:1, high-performance gliders can be 50:1, while the typical glider is 28:1 to 30:1. To help with altitude loss near the landing site, air brakes (spoilers) can be deployed, which reduce the glide ratio to about 7:1. A slip or steep spiral can also produce significant altitude loss in the vicinity of the airport.

When entering the traffic pattern, glider pilots are taught to be closer to the runway than powered aircraft and 200 feet below pattern altitude, traveling at about 60 kts. This ensures adequate separation from faster powered aircraft. Entering the pattern poses the greatest risk for a collision, but this applies to all aircraft. Additionally, a glider pilot who mismanages his energy or gets into “sinking air” may out of necessity perform a diagonal pattern, tighten the pattern, use a non-standard right or left hand pattern, or go straight in on final. A total mismanagement of energy could result in landing downwind (only to have a twin-engine aircraft announcing a short final in the opposite direction) or result in an off-airport landing in a field. All landings are to be a full stop; go-arounds are not an option!

Who has the right-of-way when landing?

FAR 91.113(g) “Aircraft, while on final approach to land or while landing, have the right-of-way over other aircraft in flight or operating on the surface, except that they shall not take advantage of this rule to force an aircraft off the runway surface, which has already landed and is attempting to make way for an aircraft on final approach. When two or more aircraft are approaching an airport for the purpose of landing, the aircraft at the lower altitude has the right-of-way, but it shall not take advantage of this rule to cut in front of another (aircraft), which is on final approach to land or to overtake that aircraft.” Common sense, see and avoid, and head-on-a-swivel prevail.

If I want to get a glider pilot certificate, what do I need to do?

To get an add-on to your current pilot certificate, there is no written test. That’s a plus! You do not need a medical. Another plus! Succinctly, to get a Private Pilot Glider Certificate add-on, you need three (3) hours of flight time in a glider and 10 solo flights. A Commercial add-on requires three (3) hours and 20 solo flights. Both certificates require training in launching techniques, on-tow maneuvers and emergencies, along with slow flight, stalls, steep turns, and slips. If you do not hold a pilot certificate, the requirement includes a little more training and a written examination. One can solo at age 15 and get their certificate at age 16 – a year younger than powered flight certificates. We have a young lady in our club who got her glider pilot certificate and driver’s license on the same day! The cost is typically $1,500 to $2,000 for a glider add-on to a Private Pilot Certificate, and can easily be obtained in one summer.

For more information or to find a soaring club near you, check out the Red Wing Soaring Association in Osceola, Wisconsin (KOEO) at www.RWSA.org, Minnesota Soaring Association at www.SoarMN.com, or Soaring Society of America at www.SSA.org.

EDITOR’S NOTE: Woody Minar is the Chief Flight Instructor with the Red Wing Soaring Association, a Master Flight Instructor, and FAASTeam Lead Representative. The Minneapolis FAA Flight Standards District Office named Minar “Flight Instructor of the Year” in 2009 and 2012 (woody.Minar@CenturyTel.net).

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