The contents of ADs include the aircraft, engine, propeller, or appliance model and serial numbers affected. Also, included are the compliance time or period, a description of the difficulty experienced, and the necessary corrective action.

The type certificate data sheet (TCDS) describes the type design and sets forth the limitations prescribed by the applicable CFR part. It also includes any other limitations and information found necessary for type certification of a particular model aircraft. [Figure 10-1]

All TCDS are numbered in the upper right corner of each page. This number is the same as the type certificate number. The name of the type certificate holder, together with all of the approved models, appears immediately below the type certificate number. The issue date completes this group. This information is contained within a bordered text box to set it off.

The TCDS is separated into one or more sections. Each section is identified by a Roman numeral followed by the model designation of the aircraft that the section pertains. The category or categories that the aircraft can be certificated in are shown in parentheses following the model number. Also, included is the approval date shown on the type certificate.

The data sheet contains information regarding:

It is not within the scope of this handbook to list all the items that can be shown on the TCDS. Those items listed above serve only to acquaint aviation mechanics with the type of information generally included on the data sheets. TCDS may be many pages in length.

When conducting a required or routine inspection, it is necessary to ensure that the aircraft and all the major items on it are as defined in the TCDS. The inspector ensures that all installed aircraft equipment conforms to the TCDS. This is called a conformity check and verifies that the aircraft conforms to the specifications of the aircraft as it was originally certified. Sometimes alterations are made that are not specified or authorized in the TCDS. When that condition exists, a supplemental type certificate (STC) is issued. STCs are considered a part of the permanent records of an aircraft and should be maintained as part of that aircraft’s logs.

For the purpose of determining their overall condition, 14 CFR provides for the inspection of all civil aircraft at specific intervals, depending generally upon the type of operations that they are engaged in. The pilot-in-command (PIC) of a civil aircraft is responsible for determining whether that aircraft is in a condition for safe flight. Therefore, the aircraft must be inspected before each flight. More detailed inspections must be conducted by aviation maintenance technicians (AMTs at least once each 12 calendar months, while inspection is required for others after each 100 hours of flight. In other instances, an aircraft may be inspected in accordance with a system set up to provide for total inspection of the aircraft over a calendar or flight time period. These include phase-type inspections.

To determine the specific inspection requirements and rules for the performance of inspections, refer to the CFR that prescribes the requirements for the inspection and maintenance of aircraft in various types of operations.

Pilots are required to follow a checklist contained within the Pilot’s Operating Handbook (POH) when operating aircraft. The first section of the checklist is entitled “Preflight Inspection.” The preflight inspection checklist includes a “walk-around” section listing items that the pilot is to visually check for general condition as they walk around the airplane. Also, the pilot must ensure that fuel, oil, and other items required for flight are at the proper levels and not contaminated. Additionally, it is the pilot’s responsibility to review the aircraft maintenance records, and other required paperwork to verify that the aircraft is indeed airworthy. After each flight, it is recommended that the pilot or mechanic conduct a postflight inspection to detect any problems that might require repair or servicing before the next flight.

The basic requirements for annual and 100-hour inspections are discussed in 14 CFR part 91. With some exceptions, all aircraft must have a complete inspection annually. Aircraft that are used for commercial purposes (carrying any person, other than a crewmember, for hire or flight instruction for hire) and are likely to be used more frequently than noncommercial aircraft must have this complete inspection every 100 hours. The scope and detail of items to be included in annual and 100-hour inspections is included as Appendix D to part 43. [Figure 10-2]

A properly written checklist, such as the one shown earlier in this chapter, includes all the items of Appendix D. Although the scope and detail of annual and 100-hour inspections are identical, there are two significant differences. One difference involves persons authorized to conduct them. A certified airframe and powerplant (A&P) maintenance technician can conduct a 100-hour inspection, whereas an annual inspection must be conducted by a certified A&P maintenance technician with inspection authorization (IA). The other difference involves authorized overflight of the maximum 100 hours before inspection. An aircraft may be flown up to 10 hours beyond the 100-hour limit if necessary to fly to a destination where the inspection is to be conducted.

Because the scope and detail of an annual inspection is very extensive and could keep an aircraft out of service for a considerable length of time, alternative inspection programs designed to minimize down time may be utilized. A progressive inspection program allows an aircraft to be inspected progressively. The scope and detail of an annual inspection is essentially divided into segments or phases (typically four to six). Completion of all the phases completes a cycle that satisfies the requirements of an annual inspection. The advantage of such a program is that any required segment may be completed overnight and thus enable the aircraft to fly daily without missing any revenue earning potential. Progressive inspection programs include routine items, such as engine oil changes, and detailed items, such as flight control cable inspection. Routine items are accomplished each time the aircraft comes in for a phase inspection, and detailed items focus on detailed inspection of specific areas. Detailed inspections are typically done once each cycle. A cycle must be completed within 12 months. If all required phases are not completed within 12 months, the remaining phase inspections must be conducted before the end of the 12th month from when the first phase was completed.