MAULE AEROSPACE TECHNOLOGY, INC.
MAINTENANCE MANUAL
FOR
MT-7-420
9/02
27
ENGINE MOUNT:
The engine mount is a welded structure of chrome molybdenum steel (4130) tubing. The
engine is attached to the mount by means of three (3) point suspension to three (3) mounting
pads on the engine case. Each leg attachment incorporates a shock mount designed to ab-
sorb torsional fluctuation and vibrations of the engine. The engine mount assembly is bolted at
the firewall to the fuselage structure by means of four (4) 3/8” attaching bolts, (requiring a tor-
que of 160-190 in lbs.) which should be checked for tightness periodically.
An extremely close visual inspection of the engine mount should be made to periodically
check for cracks, dents, weld failures, etc., of the mount tubular members as well as the gen-
eral condition of the mount. At regular intervals, the attaching bolts at the engine should be
checked for tightness (required torque value of 37.5 - 41.5 ft. lb.) The rubber engine mounts
should be carefully inspected and replaced if necessary at each 100 hour inspection. Exces-
sive engine vibration at various RPM ranges should also prompt their inspection. Care should
be exercised to prevent the rubber mount’s contact with oil as this may result in their premature
deterioration. When torquing any engine or mount bolts, precaution should be taken against
any over-tightening, as this also may cause early failure.
PROPELLER:
The Hartzell propeller Installation, Operation and Service manual contains information on
the proper use and care of the propeller.
COWLING:
The cowling consists of an upper and lower section. Removal is accomplished by unlock-
ing the dzus fasteners and removing the AN526 screws.
A periodic inspection of the cowling should be made checking for cracks, chafing, security
of attachment, etc.
EXHAUST SYSTEM:
Check exhaust pipes for cracks. Check attachments for security.
Check the heater assembly for security and ensure that air hoses are clamped tightly and
are not worn or chafed.
FUEL SYSTEM
Two (2) 23.8 gallon main fuel tanks, mounted in the inboard end of the wings, have front
and rear outlets.
The fuel lines running from these tanks terminate at the fuel selector valve on the left side-
kick panel. The fuel selector valve has two positions: BOTH and OFF. The fuel then runs
through the firewall to the main fuel pump, then to the fuel filter. From the fuel filter, the fuel
then passes through the emergency fuel pump to the engine driven pump on to the fuel con-
