Precaution should be taken by the pilot not to taxi hard against the holdback unit. This may result in a premature release. At no time are personnel to work in front of a tensioned aircraft or deadload. If operation of the catapult is suspended for any reason, bridle tension should be released and the aircraft released from the shuttle. The shuttle and grab must not be moved along the catapult track until the track slot has been inspected and found to be clear of obstructions and all adjacent areas are clear of loose gear. Using the MANEUVER FORWARD and AFT push buttons, slowly move pistons forward and aft while all sheaves are visually checked to ensure the cables are not sliding over any locked sheaves, All personnel must be kept out of areas forward of an aircraft, or deadload positioned on the catapult, and clear of the shuttle track area during a no-load firing. All personnel must be kept clear of the area immediately behind the jet blast deflectors during aircraft turnup and launching. During night operations, do not attempt to speed up the prelaunch check of catapult components or take unnecessary chances in an effort to maintain rapid aircraft launching intervals. Sufficient time should be taken to double-check each step to prevent accidents due to faulty hookups, misinterpreted signals, and other causes. DECKEDGE PANEL AND/OR CONTROL CONSOLE. —Retraction must not be undertaken unless the water brakes are operating properly and the grab and shuttle are latched. During preheating and throughout launching operations, the difference in elongation between the two launching engine cylinders must NOT exceed 1 inch. The catapult must NOT be fired with the shuttle out of BATTERY. The shuttle must NOT be retracted with steam in receivers unless the water brakes are functioning. Do not advance the grab with spears out of the water brakes; possible grab latch damage will result, due to impact.    Therefore, use the MANEUVER FORWARD push button to advance the grab until it engages the shuttle. WATER BRAKES. —If the water-brake cylinder elbow pressure drops below 50 psi or rises above 70 psi, the water brakes should be suspended and the control console operator notified immediately. The malfunctioning water-brake pump should be secured and the standby pump started. Do not allow excessive oil to accumulate on top of the water in the water-brake reservoir. Skim off the oil, or remove it by adding fresh water and allowing the oil to flow out the overflow drain, NOTE During in-port periods, do not skim the water-brake tanks or allow the water level to reach the overflow pipe. Maintain the water level by use of bottom tank drains. This is to prevent oil from being dumped into harbors, RETRACTION ENGINE. —All loose gear and tools must be kept clear of the retraction engine and cable system. Maintain all pressures at predetermined settings. If any malfunction is observed during the advance of the grab or the retraction of the shuttle and grab, immediately SUSPEND the retract engine and notify the console operator. All sheaves must be inspected for freedom of motion before beginning a series of launchings. GENERAL. —Operating personnel should wear appropriate protective clothing to prevent burns from steam or from contact with hot metallic surfaces. Earplugs should be worn in areas of high noise level. The entire hydraulic system must be vented thoroughly and frequently, particularly after extended periods of idleness. Air in the fluid system may cause unpredictable variations in catapult performance and delays in actuation of operating components. Blowers or ventilation ducts must not be trained directly on the launching valves or steam supply area (receivers, manifold, and steam supply linen). Combustible and volatile fluids and materials must be kept away from heated catapult parts to reduce the hazard of fire and explosion. Adequate ventilation must be provided below flight deck level to prevent the accumulation of explosive vapors. 4-73