written and illustrated by Steven K.
originally published in Sensor Readings 1, April 1984
All present day aircraft have an "angle of attack" system. Angle of attack means the angle of the aircraft in relation to its optimum landing attitude. All aircraft must land at a certain speed, and the nose must be slightly up to ensure a safe landing. For example, the aircraft I worked on landed at a speed of nearly 180 knots, and the nose was up 18.3 degrees. the pilot has an indicator and a series of lights to let him know his angle of attack. The lights as they appear in the cockpit are depicted in Figure 1. If the pilot was right on the money with the nose angle and speed, the circle would light up. A ground observer would see a red light on the nose landing gear door. The top arrow lets the pilot when his plane could stall and crash. If the bottom arrow lights up, the plane's nose is too low, and the pilot must raise it. If he doesn't, he could overshoot the runway.
In most cases, the pilot must do all the work himself. There are automatic systems, but most pilots I have met prefer to do it themselves. Even with automatic systems, there is always one and on the stick.
The approach lights of the Enterprise must function in a similar manner (Figure 2). There are two ways for the shuttlecraft to land in the hangar bay. The primary mode is by use of the tractor beam, in which case the lights aid the shuttle pilot in aligning the shuttle with the beam. If the tractor beam fails, or is unavailable, the pilot must land the shuttle manually. In this case, the lights aid the pilot maneuvering the shuttle in attaining its proper landing attitude and thereby ensure a safe landing.
The tractor beam emits a patter as shown in Figures 3 and 4. The beam's extent is limited. Since a tractor beam requires a great deal of power, the range and area coverage are limited in order to conserve energy. The tractor beam is located in the shuttlebay directly above the elevator/turntable, which is the landing point of the shuttlecraft. At maximum range, the tractor beam has a diameter of 5 meters, the approximate size of the shuttle. This feature is designed to conserve energy.
The beam is composed of five areas, some of which overlap. The inner circle is the tractor beam, and coincides with the green approach light. The remaining four areas are warning areas generated by the tractor beam. When the shuttle is in the tractor beam and is straight and level, the green light on the fantail of the Enterprise will illuminate. This lets the pilot know that the shuttle is at the proper attitude for a safe landing by the tractor beam (Figure 5). Should the shuttle approach the bay outside and above the optimum angle of approach, the red approach will activate (Figure 3 and 6). This tells the pilot that he must bring the shuttle down into the tractor beam. Should the shuttle be below and outside the tractor beam, the amber approach light will activate. The pilot must bring the shuttle up to attain the proper angle of attack (Figure 7).
The off-center left and right warning lights (Figures 2, 3 & 4), let the shuttle pilot know whether he is to the left or right of the tractor beam. In Figure 8, the shuttle is to the left of the beam. The off-center left warning light be activate. The pilot must maneuver the shuttle to the right of the tractor beam. The off-center right warning light will illuminate. Thus the pilot must maneuver the shuttle to the left to align it with the tractor beam.
A combination of approach lights could illuminate. For example, if the shuttle was too high and off-center left, the red approach and the off-center left light would light up simultaneously. The pilot would then have to lower the shuttle and maneuver it to the right to align it with the tractor beam. (In Figures 6 through 9, it may appear that more than one light should illuminate. Please keep in mind that the drawings are not done to scale and are simply to illustrate a single point.)
Once the shuttle is in the tractor beam, the beam takes over and pulls the shuttle into the hangar bay for a safe landing. If the tractor beams fails, the pilot must guide the shuttle in manually. The approach beams are still generated, but the ship loses its ability to pull in objects. Thus the lights aid the pilot in maintaining his optimum approach angle until touchdown. The visual landing target in Figure 2 also helps the pilot align his craft to the proper approach when the beam fails.
The optimum approach point is a reference generated by computers when the beam is in use. This ensures that the shuttle maintains a straight and level flight ( Figures 3 & 10). The power of the tractor beam chances as the shuttle approaches. If the shuttle is 100 meters from the ship, it does no good to have the beam constantly projected at maximum range and power. This is done to conserve energy.
The flight deck officer is in the observers' dome (Figure 2 and graphic below right). He is in constant touch with the shuttle. If anything goes wrong he can take over the controls and lead the shuttle in for a safe landing.
The new fan film, Star Trek: Excalibur, has a very nice graphic which details the shuttlecraft hangar deck exterior. In this manipulated graphic, we've lit up the lights to indicate the shuttlecraft approaching is too far right and too high for a safe approach. In particular, we love the fact that they've included a flight deck officer at his post just above the clam shell, and we're looking forward to their film.
Lastly, Star Trek V: The Final Frontier seems to have repositioned the Flight Deck officer to a control room at the back of the shuttlebay. This may simply be an Flight Operations monitoring room, and not the actual flight deck office station. As with many other things with that film, this is simply something that we need to overlook.
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