Airplanes are grounded for minutes, sometimes hours at a time. The planes are shut off during this time to allow crews to perform diagnostics, and for the admission of passengers. As you sit down on the plane, you’ll notice lights come on and various mechanical noises come from the cabin. This is the normal sound of the airplane receiving a jumpstart and whirring to life. A ground power unit is needed to complete this procedure, giving the engines the spark they need to jolt to life.
Turbine Systems
Jet engines run on a system of turbines, where air is forced through to create spinning. The force of the air creates the spin, so much power is needed to lift the jet off the ground. The engines will provide this power, but they need the initial jump to begin spinning and forcing air through. That’s where turbine starting units come into play.
These units are typically portable, mounted to trailers and dragged across the tarmac. They may be mounted to the ground as well. They have a connector that fits into any standard plane, so one power unit can typically service an entire fleet of planes just based on connection type. However, these units have charges and fuel levels of their own. It’s not uncommon to find several hundred of these units in a major commercial airport for efficiency’s sake.
Power in Airplanes
Cars run on batteries, and they are charged as you drive. The battery holds enough of a charge to turn the engine over, then your car does the rest of the charging itself as you move. Planes don’t work like that.
Planes use an auxiliary power unit to power the rest of their system, so you can think of jumpstarting a plan as something you do in phases. The first step is hooking the APU up to the ground unit, then the APU is fired up. That energy is then used to power the remaining flight systems and get the plane ready for take off. An APU is like turning the key halfway on a car. The plan can perform most of its cabin functions, like AC or lighting, but doesn’t have the juice to take off.
Final Thoughts
An airplane starting unit has to meet specific criteria before it can be used on a commercial aircraft. New guidelines demand charging units that have a starting range of up to 43,000 feet, which is related to the altitude where a plane might receive a jump.
Related Story: Auxiliary Power Unit