Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 647 / 1956

PAGE 1
Feb 28/07
3H7
29-00-00
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
GENERAL
1. Description and Operation
The hydraulic system components covered in this chapter consist of the combination hydraulic pump/
reservoir and hydraulic lines. The brake system, although hydraulically operated, is not included in this
section as it has its own hydraulic system independent of the gear system. The brake system and
landing gear are covered in Chapter 32. The flap system in this aircraft is electric and is covered in
Chapter 27.
WARNING: PRIOR TO CHECKING OUT THE HYDRAULIC SYSTEM, PLACE THE AIRPLANE ON
JACKS. (REFER TO JACKING, 7-10-00.)
The hydraulic system provides the power to operate the landing gear using an electrically driven
hydraulic pump operating at 1350 to 1400 maximum psi. The hydraulic pump is located behind the aft
baggage compartment with access through a removable panel. The pump has a fluid sight gauge for
ease of checking fluid level, as an integral part of the unit. A relief valve in the pump prevents system
pressure from exceeding 1600 psi during pump operation. A thermal relief valve prevents hydraulic
pressure from exceeding 2600 psi when the landing gear is down and locked and airplane is on the
ground.
The landing gear selector is an electrical switch that commands the pump to operate in either the up or
down position. The gear is held in the up position by hydraulic pressure. Emergency gear extension is
accomplished by a free fall function of the gear selector valve which releases gear up hydraulic pressure,
allowing the gear to extend and lock.
2. Troubleshooting
If trouble develops in landing gear, place the airplane on jacks (refer to Jacking, 7-10-00), and proceed to
find the cause of the trouble. A hydraulic system operational check is provided under Hydraulic System
Testing, 29-10-00. See also Landing Gear Retraction System Functional Test, 32-30-00. When the
trouble has been recognized, the first step is to isolate the cause. After isolation of a particular cause or
problem, refer to the individual Chapter pertaining to that subject matter, i.e. Landing Gear: Chapter 32.
Hydraulic system troubles are not always traceable to one cause. It is possible that a malfunction may be
the result of more than one trouble in the system. Start with the most obvious and most probable
reasons for the trouble, check each possibility and, by process of elimination, isolate the troubles.
3. Hydraulic System Leading Particulars
See Charts 1 and 2.