IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved
05-20
March 2020
Page 9
IO-390-D Series Engine Maintenance Manual
05-20 - REQUIRED ENGINE INSPECTIONS FOR IO-390-D SERIES ENGINES
1.
Engine Inspections
A.
As shown in the Engine Inspection Schedule in Chapter 05-10, the scope of engine
inspections includes visual observations during engine servicing or maintenance as well as
inspections based on progressive time intervals after the engine is put into service.
B.
All engine inspections are mandatory and must be completed no later than 10 hours after the
specified time interval for the inspection. Refer to FAR 91-409 for additional requirements.
NOTICE:
More frequent inspections could be necessary for engines operated in particulate-
laden or extremely humid, cold, damp environments.
Obey and follow inspection checklists and instructions in this chapter in addition to
maintenance guidelines from the aircraft manufacturer or component manufacturers
that have a Supplemental Type Certificate (STC).
2.
Visual Inspection for IO-390-D Series Engines
A.
Complete the Visual Inspection, with the engine installed in the aircraft, before the initial 10-
hour inspection and each routine 25, 50, 100, 400, 500, and 1000-hour inspection and every
time before you service, maintain, clean, or disassemble the engine.
WARNING
BEFORE ANY ENGINE INSPECTION OR SERVICE PROCEDURE, MAKE
SURE THE IGNITION SWITCH IS SET TO OFF AND THAT ALL POWER
TO THE ENGINE IS DISCONNECTED. ENSURE ALL
OBJECTS/PERSONNEL ARE CLEAR OF THE PROPELLER’S
ROTATIONAL ARC. IF POWER IS ON, A LOOSE OR BROKEN WIRE CAN
CAUSE THE ENGINE TO START AND THE PROPELLER TO TURN
WHICH CAN LEAD TO DEATH OR SERIOUS INJURY OR A PROPELLER
STRIKE.
B.
Visual Inspection
(1)
Set all ignition and electrical switches to the OFF position.
(2)
Per the aircraft manufacturer’s instructions, remove the engine cowling from the aircraft
for access to the engine and its compartment.
CAUTION
IF VOLCANIC ASH IS SUSPECTED ON THE ENGINE, DO NOT
TOUCH IT WITH BARE HANDS OR GET IT IN YOUR EYES.
WEAR PERSONAL PROTECTIVE EQUIPMENT. DO NOT USE
WATER TO RINSE IT OFF. THE VOLCANIC ASH CAN CONTAIN
ACIDIC COMPOUNDS WHICH MUST NOT BE INHALED OR
TOUCHED SINCE IT CAN CAUSE INJURY. REFER TO THE
"VOLCANIC ASH REMOVAL" PROCEDURE IN CHAPTER 05-30.
(3)
Copy and complete the Visual Inspection Checklist in this chapter for IO-390-D Series
engines each time this inspection is done as a record of engine service. Record the engine
hours.
NOTICE:
Except as noted, in this chapter the term “magneto” can refer to either the Lycoming
Electronic Ignition System (EIS) or optional, traditional magnetos, depending on the
type of system installed on the engine.
