An HP .... consists of 3 or 3 booms with a cage at the end which will hold 1, 2 or 3 persons. In the travellling position, the cage hangs off the back of the vehicle. Used as a water tower using a fixed monitor, rescue platform, lighting tower, observation platform.
A TL ...... very long set of ladders with an option of a two person cage that can be fitted if required. Used for rescue, water tower when the monitor has been fitted, or sometimes a lighting tower if additional floodlighting can be fitted.
An ALP (usually seen at sporting events with a cameraman at the top) is an adaption for fire fighting of an aerial access platform normally manufactured by Bronto of Finland ...... consisits of 2 booms ..... one telescopic similar to a crane jib and one fixed with a cage attached. When in the travelling position, the cage sits under the boom package on the decking, so there is no overhang.
The booms have a telescopic rescue ladder attached to the side for performing multiple rescues or for the crew to get down in an emergency. Dependant on size, the cage capacity can be up to 5 persons.
All the appliances have their own attributes and capabilities, but don't confused with thinking that an ALP is a hybrid ....... it isn't!!!