SAFEST SOARING SITE IN NORTH AMERICA

 

You’re probably wondering how we could make such an audacious claim in view of the many soaring sites in North America and the lack of consensus on safe standards against which to measure such a ranking. Here’s why we think Avenal is the safest soaring site in North America.

 

These are the elements that make up our concept of a “safe site”:

 

  1. Elevation (msl) of the gliderport.
  2. Mixed use of gliders and other aircraft.
  3. General weather patterns.
  4. Length, width and orientation of the runways.
  5. Obstructions on or near the gliderport.
  6. Surface of the runways.
  7. Land out sites near and far.
  8. Expectation of lift within a radius of 10 miles of the gliderport.
  9. Types of lift encountered all year.
  10. Control of on-field operations.

 

Here’s how Avenal measures up to these elements:

 

  1. At 780 ft msl, Avenal is not plagued with high density altitude days and the attendant problems present during such days. Even during the infrequent days in mid-summer when the on-field temperature reaches 107, the density altitude increases to only about 3500 ft. For most of the year, the tow planes have no trouble towing large gliders at full gross weight nor do glider pilots concern themselves with the ever-present conditions of gliderports at higher altitudes.
  2. Avenal is a dedicated gliderport, owned and controlled by glider pilots for and about the sport of soaring. Avenal is not a public use airport. We can and do restrict movements on the field. It is shown as a Restricted airport on both the Los Angeles and San Francisco Sectional charts. We allow mixed use of gliders and other aircraft only when those other aircraft are visiting for soaring purposes and not simply stopping by or training in the pattern or the surrounding area.
  3. The general weather patterns at Avenal can best be described as “benign”. Rarely do we see monstrous thunderstorms, damaging hail, monsoonal rains, severe winds, destructive turbulence, and dangerous roll clouds. We soar all year around because we have a pleasant combination of the four sources of lift; thermal, convergence, slope, and mountain wave. We don’t usually get above 17,000 msl in wave, but neither do we get the negatives associated with such heights. Sure, we see very strong thermals significantly above 1000 fpm, the winds do blow sometimes at 30 knots on the ground, and the convergence/shear line can be quite turbulent. But none of those produce anything but great fun, superb soaring conditions and challenges for all the skill levels of our club members.
  4. Our runways are easily accessible, wide, and long enough for any type of soaring activity. The main runway, Rwy 31/13, is 3400 feet long and 400 feet wide. Runway 07/25 is 2600 feet long and 200 feet wide. Runway 16/34 is 2600 feet long and 200 feet wide. Operations are frequently conducted on runway 31/13 in both directions simultaneously with a significant degree of safety. The gliderport is essentially a right triangle with runways at all three sides. Because of this orientation, no one need make a severe crosswind takeoff or landing. Certainly we practice such maneuvers for obvious reasons, but given an unannounced wind shift while gliders are airborne, no one need sacrifice safety by trying to land on just one runway. Our three runways provide one more element of protection against unanticipated wind changes making runway selection safe and reasonable.
  5. There are no trees, buildings, antennae, tanks, towers, wires, or any other obstructions higher than a cow fence at four of the six runway ends. The fifth end, the approach to runway 34, has a small grove of short trees just off the end of the runway. The sixth end has a 15-foot high telephone line about 100 feet from the approach end of runway 25. In four of the six ends, beyond the cow fence there are no obstructions at all for more than three miles in each runway heading direction. Flat smooth pastureland is all one sees upon approach or takeoff. The approach end to runway 25 is over the southeast portion of the city of Avenal. There are no tall buildings over two stories high in the city. There are no obstructions within the triangle formed by the three runways except for the windsock and wind tee. Emergency landings can be made at nearly any point on the surface of the gliderport consisting of 92 acres. Given that one can land a glider in the space of a quarter acre or less, there are at least 350 sites on the field where a glider can be safely landed. At the departure ends, rope breaks, real or practiced, present very little hazard with a safe return to the gliderport rarely in doubt. Further, since the land continues level from the gliderport in all directions, there is virtually no geographic condition present that would cause dangerous wind shear conditions to exist on takeoff or final approach.
  6. The runway surfaces are all hard packed dirt with large patches of grass in the winter and dried grass in the summer. As many power pilots will attest, touchdown on such surfaces gives a “soft” feel. Further, if one fails to lower one’s gear upon touchdown, little more than a few scratches will appear on the underside of the glider. Not so with a hard surface runway. What happens when it rains hard on the field? We don’t fly until it cakes over. Given the meteorological history of Avenal including average annual rainfall, soft field conditions rarely exist.
  7. Practicing cross-country soaring? This is a safe place to learn. There are literally thousands of acres of pastureland within a hundred mile radius of Avenal where landouts are no more upsetting than landing back at Avenal. There are also hundreds of crop duster strips many not shown on NOAA Sectional charts but easily seen from the air. Recently, 60,000 acres of farmland just to the east of Interstate 5 and northeast of Avenal across the Kettleman Hills have been taken out of cultivation permanently by the Federal Government in a settlement with West Side farmers. These will, in a year or so, make up another huge area of safe landout sites. So, whether trying for silver or diamond distance, if you want to learn cross-country soaring, no better place to do it than here at Avenal.
  8. Most of our Annual Contest competition pilots refer to it as the “Avenal Effect”. For what must be a combination of geographic and meteorological reasons, lift within a ten-mile radius of Avenal is legendary. One might be trying to return to Avenal and perhaps ten miles out, convinced a landout is imminent, stays the course and enters the ten-mile radius where this effect is most strongly felt. Ask the pilots who’ve encountered this phenomenon.
  9. We soar all year long at Avenal because the lift conditions vary enough to allow continued operations. In the spring we have thermal, convergence, and occasionally mountain wave. In summer, most soaring is done in thermal or convergence. In fall, storms begin their annual cycle and in addition to thermal and convergence, wave begins and ridge soaring is encountered. In winter, Tule fog is present occasionally and the cool air makes for great primary training. This allows the student to master the basic techniques of soaring and by the time the weather turns into large areas of instability, the student is well prepared for it. But winter is also the best time for wave flying. Interestingly, the correct point at which one soars in the wave is nearly right over the field at Avenal. We have often sat on the patio, looked up and monitored various pilots’ progress in the wave. Talk about the convenience of home field advantage. But why is year around soaring an element of safety? Because there are no mid-winter gaps in the opportunity to maintain and improve one’s flying skills.
  10. Because Avenal is a non-profit club operation and not a commercial venture, controls over airport operations are governed by safety and value to the club member rather than profit. This is no condemnation of all the other successful commercial operations in North America. Rather it is a statement of what one can expect at Avenal when a decision must be made regarding our soaring operations. A high level of safety and a legendary economic soaring value are the basics of our operation and will remain that way for as long as glider pilots own the field and control the glider operations.

 

We encourage others to challenge our definition of “safe site” and how Avenal measures up against that definition. If there exists another soaring site in North America that can demonstrably claim to be a safer site, we will be happy to relinquish our current self-declared supremacy.

 

Sincerely,

 

Central California Soaring Club.

 

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