Maintenance Records

Maintenance Records

Are they all there or do we need more?

Joe HertzlerBy Joe Hertzler

February 2001

The Logbooks – Is that all there is?
When it comes to aircraft logbooks, the format that they are set up in can vary drastically from aircraft to aircraft. Regardless of the format or quantity of logbooks and maintenance records, the question arises "What content is required by regulation?"
14 CFR Part 91.417. spells out what maintenance records are required and how long those records must be kept by the owner/operator. For simplification, maintenance records called out in this rule can be divided into two categories - permanent records and expiring records.

Permanent records
Permanent records are those maintenance records that must be kept and maintained for the aircraft indefinitely. They reflect the current "status" of the aircraft. 14 CFR Part 91.417 (a)(2) lists the permanent records that must be "retained and transferred with the aircraft at the time the aircraft is sold." Let’s discuss each type of record specifically addressed by the Regulation.

Total time-14 CFR Part 91.417 (a)(2)(i)
Having record of the total time in service of the airframe, each engine, and each propeller and each rotor simply involves keeping track of time accumulation. "Time in service" essentially means; from the time the tires on the landing gear leave the ground to the time the tires touch back down. This can get tricky when engines, propellers, and rotors are replaced with new or time continued components. After carrying over the correct times, there will be several different total times to monitor and tally up each time. It is the responsibility of the owner/operator of the aircraft to know and provide the aircraft total time to the FAA and to maintenance personnel when required. Although maintenance record entries only require total time references when an inspection is accomplished (Ref 14 CFR 43.11), it is highly recommend to record all applicable total times and cycles in every maintenance record entry whenever possible.

Life limited parts-14 CFR Part 91.417 (a)(2)(ii)
Life limited parts are those parts that have received a specific life limit from an approved FAA document for that aircraft. Some examples of FAA-approved documents are the Type Certificate Data Sheets (TCDS), Approved Airplane Flight Manual, the FAA Approved Airworthiness Limitations Section of the aircraft maintenance manual and Airworthiness Directives.
With the exception of life limited parts called out by ADs, life limits generally begin with the Type Certificate. The Type Certificate will contain either specific reference to parts numbers that are required to be replaced at a specific time or refer us to a document that contains such information. To determine what parts are "life limited" for your aircraft, it is usually best to start with the Type Certificate Data Sheet and follow the road signs from there.
The Regulation refers to the "current status" of life limited parts. To know the current status of life limited parts we need to know the following questions:
1. Which parts are life limited?
2. What are their serial numbers?
3. What are their life limits
4. How much of the limit is left?
Additionally, some life limited parts must be replaced based not upon total time in service, but upon total cycles in service. When the life limited parts replacement requirement calls out replacement of a part at a total cycle count of XYZ, and we don’t know the total cycle count, we cannot demonstrate that the part is not past the limit. The situation then mandates tracking of landings and cycles in order to demonstrate compliance.

Time since overhaul-14 CFR Part 91.417 (a)(2)(iii)
Overhaul times are generally called out in maintenance manuals and service information. The maintenance manual usually lists the items that the manufacturer requires be overhauled. The rule requires that we be able to show the time since last overhaul for those items.
Incidentally, this rule does not mandate the overhaul of such items, just the recording of the time since last overhaul. For operations conducted under 14 CFR Part 91, overhaul is not a mandatory requirement as long as the item continues to pass required inspection criteria, although it is usually very desirable to perform overhauls at the recommended intervals.

Inspection Status-14 CFR Part 91.417 (a)(2)(iv)
14 CFR Part 91 discusses inspection requirements. The requirements can vary greatly depending on aircraft classification. They can range from annual inspections on G.A. aircraft to phase inspections on the larger more complex ones. Special inspections that are tracked by landings or cycles may also need to be recorded.
In order to be able to provide the current inspection status of an aircraft required by the rule, the following should be answered:
1. What inspection program has been selected for the aircraft?
2. What are the required look phase inspections and special inspection for my airframe, engines, propellers, rotors, appliances, survival equipment, and emergency equipment installed on my aircraft?
3. When was the last time that each of the required inspections was accomplished?
4. When is the next time each items is required to be accomplished again?

Airworthiness Directives-14 CFR Part 91.417 (a)(2)(v)
Accurate and complete maintenance records will include proper documentation of AD compliance throughout the records as each AD is complied with. It is only practical however, to create a list of all applicable AD’s and identify in that list, the information required by this rule:
• The AD Number
• The Topic of the AD (optional)
• The revision or effective date of the AD (not the amendment number)
• The method of compliance for the AD
• If the AD requires recurring action, the time and/or cycles and date it will next be due

Major Alterations (FAA Form 337)14 CFR Part 91.417(a)(2)(vi)
This rule requires that only FAA Form 337’s that document Major Alterations need to be retained permanently and transferred with the aircraft. However, the value of the aircraft can be greatly impacted without all FAA Form 337’s. It is usually a good idea to keep all 337’s including those for Major Repairs - even if they are kept in a separate binder. This practice can also assist maintenance personnel who may need to refer to a 337 in order to answer maintenance questions.

Expiring Records-14 CFR Part 91.417 (a)(1)
Now, let’s talk about items we will call expiring records.
14 CFR Part 91.417 (a)(1) reads as follows:
(1) Records of the maintenance, preventive maintenance, and alteration and records of the 100-hour, annual, progressive, and other required or approved inspections, as appropriate, for each aircraft (including the airframe) and each engine, propeller, rotor, and appliance of an aircraft. The records must include:
(i) A description (or reference to data acceptable to the Administrator) of the work performed; and (ii) The date of completion of the work performed; and (iii) The signature, and certificate number of the person approving the aircraft for return to service.
Maintenance records that fall into this category are required to be kept until the work is accomplished again or for a period of 12 months (Ref 14 CFR Part 91.417 (b)(1)). This indicates that these records, if not superceded by new identical records within the first 12 months following approval for return to service, may be discarded. (CAUTION: DON’T DISCARD THOSE RECORDS). Expiring records include, maintenance performed (including Major Repairs), preventive maintenance performed, minor alteration records, and records of inspections. Although inspection records (100-hr, annual, and progressive) do not need to be retained when they have been superceded within the required 12 months, this does not alleviate the requirement to keep the current status of inspections.
Next issue we will wrap up our Maintenance Records Topic in a discussion about the impact of accurate maintenance records on the value of the aircraft and the re-generation of lost or stolen maintenance records.