Obstacle avoidance (Part 1 of 2)
If it weren’t for obstacles and obstructions, I could probably teach students to fly a balloon in about 2 days. Unfortunately, these “things” seem to get in the way, usually during takeoffs and landings. The method for successfully dealing with obstacles requires a simple 3 step process (most of the time).
- Recognize they are there (see them).
- Know how fast and which way the wind is going between you and the obstacle.
- Have a plan of evasive action in mind well before the approach to the obstruction
As usual, this requires thinking ahead.
I don’t know the statistics on obstacle collisions but I would bet that most of them occur during landing. At take off, we have some choices that help mitigate our chances of collision. However, I still see many students leave more to chance than necessary at launch. It is very crucial that the pilot look at the entire field and pick a spot that allows for a 90 degree sweep with no obstructions on either side if possible. If you are sharing the field with others, this may not be possible. Please don’t launch within a 30 degree roll of a fenceline when you have an entire field.
Once inflated, aside from basket housekeeping and passenger conversation, you must notice and evaluate all of your threatening obstacles (fan, chase vehicle, trees, powerlines, recently or nearly inflated adjacent balloons). The next step is to re-evaluate the low wind direction and determine which obstacles are within 40 degrees (either side) of that direction. A very clear plan of evasive action must be formulated at that point. It may be as simple as developing an ascent rate to clear a 30’ tree at the end of the field. However, it could be planning a sudden rapid ascent to clear an inflated balloon 40 degrees to the left of your intended travel path if necessary.
In the case of a “calm” take off, the assistance of the ground crew can minimize many surprises. The crew person (one of them) should be instructed to “weigh off” the balloon and gently push it away (no down pressure) from the close obstructions at “ground break”. Consequently, “ground break” should be slow and controlled with the take off plan being the only focus of the pilot. I see many pilots jumping up and down in the basket just before liftoff trying to determine how far off equilibrium is. It’s much easier to burn long burns in rhythm leaving time to re-oxygenate the mouth. When the balloon breaks ground (it will not be sudden), burn solid until the basket is about 6” (no more) off the ground. The ensuing ascent will be smooth and controlled.
Once in the air, for the most part, obstacle avoidance is simple. When obstructions seem to get bigger; burn. Quit burning when they get smaller. Seriously, there are a few situations that require some mental skills while aloft. One of these is flight in the vicinity of a high tower. The obvious hazards with respect to a tall tower is the tower itself and the guy lines. The real problem lies in knowing how fast and in what direction the winds between you and the tower are. For example, if you are at 1000’ and a half mile away, currently heading 20 degrees to the outside of a guy wire on a 2000’ tower, you intuitively begin to think (I hope) that you might want some altitude up ahead to insure tower or guy line clearance in case of a wind shift.
You begin to climb, assured with the knowledge that you could clear the top of the tower from here if necessary. As you climb, you notice more turn towards the tower and the wind is accelerating. All of the sudden, you realize that your closure rate on the tower has increased and the balloon is aiming more for the center of the tower as you climb. At some point, it is clear that you can’t clear the top of the tower. I think you get the point.
Going from one point in the flight where you would likely miss the outer most guy wire by staying at 1000’ to a collision with a tower would appear in retrospect to be pilot error. However, most experienced balloon pilots would make the intuitive decision to climb in order to avoid the “bite” when adjacent to the tower. It is instilled in all competent balloonists never to invoke the “hope” syndrome but rather to proactively fly to avoid downwind obstacles. This situation and similar ones do come up on occasion through the life of a balloon pilot. It is imperative that the pilot “think” this type of situation through well ahead of time and not surrender to experienced intuition.
Several ways to deal with this situation are to “notice” where the tower is just after liftoff. We are assuming here that the launch area is miles away and downwind of the tower. At any time during the flight, at the first sign of a turn towards the tower, a different wind should be found immediately to insure a track at least 20 (preferably 40) degrees away from the line to the tower (unless you immediately decide to go over). If for any reason you failed to follow the above plan and find yourself in the original situation described above, one course of action is to quickly descend out of the accelerating winds, dive to landing altitude and try to steer around the outermost guy wire. Invoking the “hope” syndrome? No.
Along with the plan to steer around the wires is the fact that the pilot must be prepared to ditch at any point that the winds don’t allow circumnavigation of the guy wires. While steering, the pilot must also “visualize” possible turns towards the wires and spot the least hazardous ditching points in case of a bad turn. The pilot must be prepared to drop the balloon in a road, a tree, a house or some other obstruction if necessary. With proper planning, a powerline should not be one of the options. This scenario is not a suggested practice but would be a better alternative to collision with a tower.
Most of the time, if a pilot follows good ballooning fundamentals (think way ahead and plan accordingly), he/she will be blessed with many safe and wonderful flights. However, on a some occasions, it is prudent to thoroughly evaluate all possible outcomes before making a flight decision.