- 2 -
ing the aircraft engines the flight engineer used the electrically driven auxiliary hydraulic pump to build the hydraulic pressure to 3000 p.s.i. in the accumulators. The emergency hydraulic pump elector valve lever was then placed in the normal forward (brakes only) position. The engineer said that he did not move the by-pass lever,[1] and that in accordance with the checklist, it was in the down position. While performing other associated duties the flight engineer noted in the log that hydraulic work had been done on the aircraft.
When the captain and the first officer boarded the aircraft the flight engineer advised the captain that the checklist had been completed. The captain then set the parking brakes.
Shortly before the engines were started a Delta mechanic entered the flight deck and explained to the captain the modification that had been made in disconnecting the Meletron switch and capping the hydraulic line to the switch. He also explained that disconnecting this unit in no way affected the normal operation of the hydraulic system.[2] The mechanic stated that the captain, at his request, operated the auxiliary hydraulic pump; and both men were satisfied that the pump operated.
After performing their assigned functions in the cabin the stewardesses both went forward to the cockpit to observe the takeoff from the flight deck. One occupied the observer's seat directly behind the flight engineer and the other seated herself in a jump seat near the crew entrance door.
- ↑ The by-pass valve mechanically operated by the hydraulic system by-pass lever permits hydraulic fluid to be by-passed directly from the engine-driven pumps to the reservoir. The lever is placed down during ground operation and up in flight when pressure to the various hydraulic units is not desired. The lever is spring loaded to the down position.
- ↑ The hydraulic system of DC-7 aircraft consists of the following individual but interconnected components:
(a) The main pressure supply system which utilizes the engine-driven hydraulic pump and the pressure regulator to supply pressure to the hydraulic system for operation of the hydraulically actuated units.
(b) The main pressure accumulator system which provides a reserve supply of fluid under pressure and dampens fluctuations of pressure in the hydraulic system.
(c) The emergency pressure supply system which utilizes an electrically driven hydraulic pump to supply pressure to the hydraulic system for operation of the hydraulically actuated units if pressure is not available from the main pressure supply system. Two switches operate this system. One switch is located to the left of the captain's station, the other to the right of the copilot's station.
(d) The hydraulically actuated units which receive fluid under pressure from the pressure supply system to operate the landing gear, wing flap, brakes, etc.
