Maintenance Records Overview
Twisted-Wrench LLC   Aircraft Maintenance Special Projects
What do you need to learn about
Maintenance Records?

What is Airworthiness? 91.403

What is in Part 39 Airworthiness Directives? 91.403

What are appropriate entries in the Maintenance Record? 91.405

What is an appropriate return to service? 91.407

Who is authorized under Part 43.7?

What is an appropriate maintenance entry as required by Part 43.9 or

91.403   General

(a) The owner or operator of an aircraft is primarily responsible for
maintaining that aircraft in an airworthy condition, including compliance
with part 39 of this chapter.

91.405   Maintenance required

(b) Shall ensure that maintenance personnel make appropriate entries in
the aircraft maintenance records indicating the aircraft has been approved
for return to service;

91.407   Operation after maintenance, preventive maintenance,
rebuilding, or alteration

(a) No person may operate any aircraft that has undergone maintenance,
preventive maintenance, rebuilding, or alteration unless—

(1) It has been approved for return to service by a person authorized under
43.7 of this chapter; and

(2) The maintenance record entry required by 43.9 or 43.11, as applicable,
of this chapter has been made.
Regulatory Requirements for Owner and Pilots
Find answers in this website
How many kinds of Maintenance Records are there?
1.        Records of Maintenance including Major Repairs
  • Repairs, including Major Repairs
  • Component Replacement
  • Airworthiness Directive Compliance
  • Service Bulletin Compliance

2.        Records of Alterations, including Major Alterations
  • Add, Delete, or Change Equipment
  • Alter Aircraft Specifications
  • Airworthiness Directive Compliance
  • Service Bulletin Compliance

3.        Records of Inspection Including
  • 100 HR
  • Annual
  • Progressive
  • Other
  • Airworthiness Directive Compliance
  • Service Bulletin Compliance

4.        The total time in service of the airframe, each engine,
each propeller, and each rotor


a. Time-in-service recording devices sense such things as electrical power on, oil
pressure, wheels on the ground, etc. , and from these conditions provide an indication of
time-in-service.  With the exception of those that sense aircraft lift-off and touchdown, the
indications are approximate.
b. Some owners and operators mistakenly believe these devices may be used in lieu of
keeping time-in-service in the maintenance record. While they are of great assistance in
arriving at the time-in-service, such instruments, alone, do not meet the requirements of
9 1.417. For example, when the device fails and requires change, it is necessary to enter
time-in-service and the instrument reading at the change. Otherwise, record continuity is

5.        The current status of life-limited parts of each airframe,
engine, propeller, rotor, and appliance

6.        The time since last overhaul of all items installed on the
aircraft which are required to be overhauled on a
specified time basis

7.        The current inspection status of the aircraft, including the
time since the last inspection required by the
inspection program under which the aircraft and its
appliances are maintained

8.        The current status of applicable airworthiness directives
(AD) and safety directives including, for each, the
method of compliance, the AD or safety directive number
and revision date.

    If the AD or safety directive involves recurring action, the time and date
    when the next action is required.

9.        Copies of the 337 forms prescribed by 43.9(d) for each
major alteration to the airframe and currently installed
engines, rotors, propellers, and appliances