10-foot    lower    structure,    a    variable    height    upper structure,    and    a    manual    pump    actuated    hydraulic system  for  raising  and  lowering  the  upper  structure. The   upper   structure   includes   a   work   platform   with guardrails and steps with handrails. The lower structure includes fixed steps and handrails, a towbar, and four free-swivel caster wheels with safety locking devices, four immobilizing jacks, and a hydraulic pump, lines, and   reservoir.   The   height   range   for   the   B-2   work platform is from 13 feet to 20 feet, and it has a weight bearing capacity of 600 pounds. B-4  MAINTENANCE  PLATFORM.—The  B-4 maintenance    platform    (fig.    9-30)    is    a    moveable, hydraulically    operated,   adjustable    platform   with   a ladder assembly. Four free-swivel caster wheels, each having   a   foot-lever   actuated   mechanical   brake   and swivel lock mechanism, are included. The platform is equipped   with   safety   guardrails,   handrails   for   the ladder, two safety lock pins, which are inserted into the frame to lock the extension scissors of the platform.  A hydraulic  hand  pump  with  reservoir  is  provided  for raising   and   lowering   the   platform.   The   adjustable height range for the B-4 work platform is from 3 to 7 feet and a weight bearing capacity of 600 pounds. Q9-1.   What are the two types of support equipment? Q9-2.   The  primary  function  of  the  A/S32A-30  tow tractor is to tow what aircraft or equipment? Q9-3.   What tow tractor is designed for towing air- craft aboard ship? Q9-4.   What  type  of  tow  tractor  is  designed  to  tow, turn, and position aircraft within the confines of an aircraft carrier hangar deck and is often called "The Spotting Dolly"? Q9-5. What   aircraft   crash   handling   and   salvage crane is used on amphibious assault ships? Q9-6.     Aboard ship, what is the primary fire-fighting and rescue vehicle? Q9-7.     What fire-fighting agents are contained in the twinned agent unit (TAU-2H)? Q9-8.     What  activity  is  tasked  with  maintenance  of forklifts aboard naval stations? Q9-9.   What mobile electric power plant is designed primarily for use on aircraft carriers? Q9-10.    What type of motor propels the NC-8A mobile electric power plant? Q9-11.     What is the danger associated with operating the   NC-8A   or   NC-10C   when   aircraft   are serviced? Q9-12.    The A/M47A-4 jet aircraft start unit provides what support for starting aircraft? Q9-13.    What are some of the dangers associated with operating a jet aircraft start unit? Q9-14.    The A/M27T-5 is used to service what aircraft system? Q9-15.    How many nitrogen gas cylinders are mounted on the A/M26U-4 (NAN-4) servicing unit? Q9-16.    What are the major components on the TMU 70/M oxygen storage tank? Q9-17. What  is  the  purpose  of  having  mobile  air- conditioning units? Q9-18.   What type of aircraft jack is used to raise the entire aircraft off the deck? Q9-19.    What is the weight bearing capacity of the B-4 maintenance platform? MAINTENANCE REQUIREMENTS LEARNING OBJECTIVE: Identify the purpose for support equipment preoperational maintenance and the requirements for support equipment    training,    licensing,    and    misuse/ abuse. You, as an Airman Apprentice, are not responsible for   maintaining   support   equipment,   unless   you   are striking  for  Aviation  Support  Equipment  Technician. You   will,   however,   be   required   to   operate   support 9-18 SAFETY RAILS LOCK PINS PARKING BRAKES ANF0930 Figure 9-30.—B-4 maintenance platform.