it also temporarily causes the pressure ceiling to drop. When the envelope becomes full (i.e., reaches its pressure ceiling),
gas is expelled and a new ceiling is established.
If the flight is continued through sunset, loss of solar heating results in a cooling of the lifting gas and a resultant loss of
gross lift. Ballast must then be used to maintain buoyancy.
Purity of Lifting Gas
A final topic of interest is the effect of mixing air with the lifting gas. It may seem that since air is heavier than the lifting
gas, the air would have a tendency to pool at the bottom of the envelope and be expelled through the appendix as the
balloon rises into less dense air. However, this is not what happens. The forces of molecular attractions cause the air and
lifting gas to become permanently mixed and a generally less pure mixture occurs. When this happens, some of the benefits
of operating under the pressure ceiling are lost and every up/down maneuver causes the loss of lifting gas along with the
expelled air.
For this reason, care should be taken to close the appendix when descending rapidly to avoid allowing air to force its
way up into the envelope through the open appendix. Maintaining a high level of purity of the gas inside the envelope
can extend flight duration. Care must be taken to open the appendix during rapid or prolonged ascents which bring the
balloon close to its pressure ceiling. Ascent above pressure ceiling with a closed appendix increases internal pressure on
the envelope’s fabric and, in an extreme case, could cause the envelope to rupture.
Landing, Retrieval, & Packup
The landing phase is the single most critical portion of the entire flight. The pilots may be fatigued from the long flight.
They may be in unfamiliar geography and weather conditions. There may be time pressure to land in daylight if sunset is
approaching. A landing after dark, under a full moon and in open territory may be performed rather routinely, but a daylight
landing is still much preferred. A night time landing in dense woods under a new moon or with reduced visibility can be
very stressful. Five minutes on oxygen prior to landing may help to relieve some fatigue and clear the senses.
The landing decision varies with each flight and should be discussed jointly among all the pilots. Landings should be
initiated while there is still adequate ballast available to abort at least one approach, if necessary. The actual amount of
ballast required varies with pilot experience, weather conditions, terrain and descent rate. For a 1,000 cubic meter balloon
in relatively easy landing conditions and under a shallow descent, 50 pounds may suffice. Under more adverse conditions,
250 pounds or more may be advisable. Additional considerations for landing may include duration of flight, fatigue level
of the pilots, accomplishment of the flight objectives, current and forecast weather, terrain, and time of day.
When the decision is made to land, all possible equipment should be securely stowed. Occupants should don helmets and
any other protective gear. All antennas, solar panels, and other items hanging below the basket should be retrieved and
stowed. Adequate ballast should be brought inside the basket where it is readily available to abort or round-out a landing.
The trail rope should be rigged and readied for deployment. The trail rope serves three purposes. First, it slows the descent
rate. A fully deployed trail rope weighing about 40 pounds on a 1,000 cubic meter balloon normally arrests a descent of
approximately 340 feet per minute (fpm) at 150 feet above ground level (AGL) to a descent rate of 0 fpm at ground contact.
The descent from 150 feet will take about 45 seconds. These numbers are only approximations and local conditions at
landing certainly cause these to vary somewhat. Secondly, the trail rope orients the balloon so the attachment point of the
rope is on the upwind (or trailing) side of the basket. This may be important depending on the arrangement of the basket
and/or deflation ports. Finally, as more of the rope contacts the ground, friction slows the horizontal speed of the balloon.
The trail rope should be connected to the load ring with a quick release mechanism to allow release should the trail rope
become permanently entangled on the ground.
If the gondola has rotated during flight, placing the trail rope on the gondola’s downwind side, it does not deploy correctly
unless the pilot guides it around to the upwind side of the gondola. Otherwise the rope deploys under the gondola and
tends to pull the leading edge of the gondola down and may completely invert it. This is colloquially called “dog-housing”
and puts the occupants in the uncomfortable position of being dragged along the ground trapped inside the basket. Unlike
modern hot air balloons, most gas balloon systems do not have rigid uprights, so dog-housing is a real concern in a high
wind landing; the best antidote is to keep as much weight as possible (including the occupants) on the upwind (trailing)
side of the basket.
The trail rope also acts to stop any ascent since a rising balloon becomes heavier as more of the rope is lifted off the
ground. This is why it is sometimes called “retrievable” or “reusable” ballast. For this reason, the trail rope should never be
deployed until landing is completely certain. Aborting a landing with a deployed trail rope requires ballasting the weight of
the trail rope (approximately forty pounds) in addition to the ballast normally required to achieve the desired ascent rate.
The anti-sail line should be pulled tight and secured to the load ring or other strong point. The purpose of this line is to
hold the bottom of the envelope down taut to minimize drag in a high wind landing. If the envelope is allowed to ride free,
it rides up and bows in the wind, forming a scoop that catches much more wind and increases the length of the drag along
the ground.
At this point, the descent is initiated and one or more potential landing sites should be identified. If the descent continues
as expected and an adequate landing site is attainable, the descent rate should be tailored toward that site. A last check
should be made for powerlines and other obstructions on the path to the landing site. The area downwind of the site should
also be checked in case landing runs long. Only then, at a height above ground equal to the length of the trail rope (usually
about 150 feet), and only if there are no intervening obstacles between the balloon and the landing site, will the trail rope
be deployed. [Figure 11-11]
Figure 11-11. A successful gas balloon landing.
As with a hot air balloon, if a fast layer has been encountered during the descent, it may be advisable to level off at an
altitude below the fast layer to burn off some momentum. However, if this jeopardizes hitting the only likely landing site,
a high wind landing is the better option.
The final phase of the landing is ground contact, and just as in piloting a hot air balloon, a decision must be made to
perform either a rip-out or standup landing. Contrary to hot air ballooning, in gas, rip-out landings are the norm. Up to the
final moment, ascent rate is controlled by actuating the valve (or parachute) to release small amounts of lifting gas. As in
hot air ballooning, both pilots should be positioned for landing. Typically at about five feet AGL, the deflation port line
(usually red) is pulled to open the port and release a large quantity of gas immediately. Some systems may have multiple
deflation ports. Once the deflation port is activated, the flight is terminated with a rapid descent, so it is important to be
close to the ground before activation. The height of activation can occasionally be as high as thirty to fifty feet in for
emergency reasons, but a very hard landing is sure to ensue.
On the newer German (Wörner) balloons with sealing parachute tops, it is possible to reseat the parachute after a deep
activation of several seconds, but gas equivalent to many bags of ballast has been lost. Shorter, shallower vents are used
on these systems for maneuvering, but deflation is achieved with a deep constant pull on the parachute line.
Once the balloon has come to a stop and is no longer buoyant, the pilots exit and attempt to contact the chase. Any medical
concerns should be dealt with immediately. Landowners should be located, if possible, and an inventory of the contents of
the gondola should be done to check to see if anything bounced out during the landing. If darkness is near and no houses
are in sight, flashlights, a compass, and GPS should be located immediately to ensure that bearings are not lost in the dark.
On a long flight, it may be several hours until the chase crew arrives, but when they do, pack-up proceeds in reverse of
assembly.
The America’s Challenge Race, 2006
The 2006 America’s Challenge gas balloon competition is considered by many in the gas balloon community to be one of
the most exciting and controversial flights in recent years. It is presented here as an illustration of the skills and decision-
making processes necessary for a successful gas balloon flight.
In July 2006, two gas balloon pilots from Georgia, Andy Cayton and Danni Suskin, were to participate in the Gordon
Bennett challenge competition in Belgium. Upon preparation for launch, it was discovered that the balloon to be used
had some mechanical problems that kept the Cayton-Suskin team from flying. Cayton came back to the United States
with every intention of winning the America’s Challenge in the hope of having the opportunity to pursue a victory in the
following year’s Gordon Bennett. As Suskin was unable to participate in the event, Cayton selected Kevin Knapp of North
Carolina as his co-pilot for the America’s Challenge.
Launch was originally scheduled for the evening of October 7, 2006. Don Day, a meteorologist who worked with Cayton
on numerous world record hot air flights as well as other gas flights, was located at the launch field in Albuquerque, New
Mexico. In conference with Cayton and Knapp, Day determined that the weather would be a significant factor in the launch
and in any subsequent flight track across the United States. The initial track for the planned launch date would have put
the team on a northeasterly track towards Canada; but, low freezing levels and thunderstorms east of the Sandia Mountains
forced race officials to delay the planned launch. The next launch window, Tuesday, October 10, showed a potential track
east, paralleling Interstate 40.
During the 3-day weather delay, Cayton had reason to reevaluate some strategic issues regarding the flight. One concern
was the fact that both he and Knapp were fairly large men; he felt that this might place them at some disadvantage over
teams with smaller pilots. Smaller pilots are able to carry more ballast, and thus can extend their flight time. Also, while
disappointed with the no-fly situation at the Gordon Bennett, he realized that this might provide an advantage, as he would
not be attempting a second duration flight while still fatigued from the Gordon Bennett. Cayton believed that these two
issues balanced out, and continued with Knapp to prepare for the launch.
Tuesday, October 10, arrived clear and cold; the cold front and low-pressure system that had delayed the initial launch had
passed through the Albuquerque area and was now ahead of them. A massive cold front would push through Canada into
the central United States and move to the Gulf of Mexico during the second day of flight. The plan was to stay between
the two systems to remain competitive and safe. With crew chief Ken Draughn and help from competitors Peter Cuneo and
Bert Padelt, the inflation went smoothly. [Figure 11-12]
Figure 11-12. Inflation of the America’ s Challenge balloons, Albuquerque, NM, October 2006.
As launch position had been previously drawn by lot, the Cayton-Knapp team was the fifth balloon to launch. Early on the
evening of the 10th, Cayton handed two bags of ballast to the balloonmeister, Stefan Handl, and they were in the air. The
race was on! Knapp remembers many “good luck” calls from the crowd; the chase crew mounted their vehicle and departed
the launch field not knowing they would have a role in one of the most controversial events in years
Cayton-Knapp tracked more easterly than the balloons that had previously launched and stayed well north of highway
I-40 as they crossed the Sandia Mountains. Their altitude was well above 10,000 feet the first night and averaged 30 miles
per hour (mph) with the temperature in the low 30’s. Cayton and Knapp spent most of the night colder than expected and
shivering to keep warm. They established radio contact with Lubbock, Texas Approach at 0630 Wednesday morning and
shortly after experienced the magic of a sunrise from the air.
Most of Wednesday was spent flying over Texas, averaging 36 mph. Another team, that of Phil McNutt and Brian Critelli,
flew 90 degrees directly below them passing to the north just before they reached the Dallas/Fort Worth metroplex.
[Figure 11-13] Cayton-Knapp could see other balloons in the distance, but it was unusual to see another team’s balloon
so close in flight. Dallas Approach directed them to fly over the Class B airspace above 11,000 feet; at that altitude, they
started tracking a more southerly direction.
Figure 11-13. Dallas, Texas, from 11,000 feet, as seen from the Cayton-Knapp balloon in flight.
Wednesday evening found the team over northern Louisiana. Most of the night was spent above 2,500 feet flying less than
12 mph. The strategy was to stay behind the weather system ahead and to position themselves for Thursday’s flight. Cayton
and Knapp fell behind several teams during the night, but that served to let them know they were where they needed to be.
Thursday morning’s weather forecast was not favorable; winds on the surface, as well as at 3,000, 6,000, and 9,000 feet
were all going out into the Gulf with no options but to land. Several teams saw this and landed. Meteorologist Day and
Cayton had a long discussion via satellite phone, and confirmed the winds above 12,000 would hook out into the Gulf and
bring them back to dry land near Panama City, Florida. All the available meteorological information told them it would
work. If the team wished to stay competitive, they had to go high and out over the water.
They began their ascent around 10:00 AM and went out over the water just east of New Orleans. It was relatively slow
going but Cayton and Knapp finally made it back to land as planned and began a slow descent around 16:30. Equipment
was secured in anticipation of a possible landing near the Apalachicola National Forest in the Florida panhandle. After
confirming their position in the race, and with no place to land, the decision was made to continue the flight through the
night. The weather prognosis was good, the winds would be relatively calm during the night and remaining ballast was
good, so they calculated the needed distance and time to win the race. [Figure 11-14]
Figure 11-14. Panama City Beach, Florida, as seen from the Cayton-Knapp balloon, 25 miles out over the Gulf of Mexico.
Early on Thursday morning, it appeared that the team’s patience had paid off. By 0430, they were moving east about 6 mph
and were just over Cross City, Florida. At sunrise, they were 13 miles further east, and just north of Old Town and Fanning
Springs. Surface winds were calm and there was a thin layer of ground fog. As the sun came up, the balloon experienced
solar heating and ascended to just over 7,000 feet. The flight continued in an easterly direction at 15 mph and by 08:00 the
team came to the realization that they were in a perfect position to take over the lead.
As the Cayton-Knapp team crossed Interstate 75, just south of Gainesville, Florida, they received word that the German
team of Eimers/Winker [Figure 11-15, AC-13] was on the ground, and near Cayton’s home in Savannah, Georgia. Cayton
and Knapp elected to continue flying until they had a cushion of 10 miles before beginning their descent.
Figure 11-15. Tracks of the 2006 America‘s Challenge competitors.
With surface winds of approximately 3 mph and knowing the race was won, the team elected to land in Citra, Florida. Their
chase crew was waiting for them in the yard of a cooperative landowner. After a 60 hour, 20 minute flight covering 1,478
miles, Andy Cayton and Kevin Knapp had beaten the odds to capture the 2006 America’s Challenge Cup.
Chapter Summary
This chapter provides a short description of the unique aspects of gas ballooning in comparison to hot air ballooning. For
more information, a local gas pilot and the Gas Division of the Balloon Federation of America are good resources.