Dr. Mary Ann O’Grady

The Federal Aviation Administration (FAA) issues legally enforceable Airworthiness Directives or ADs for the purpose of correcting an unsafe condition in an aircraft, aircraft engine, propeller, or appliance under 14 CFR Part 39. The FAA Aircraft Certification Service maintains 12 Aircraft Certification Offices (ACOs) within four Directorates, and each one is responsible for the continued operational safety of the products over which it holds jurisdiction. This directorate responsibility is assigned by the type of product: transport category airplanes, small airplanes, rotorcraft, or engines and propellers. The Aviation Safety Engineers (ASEs) employed by the Directorate monitor the assigned products to identify unsafe conditions, and the necessity to generate airworthiness directives. These ASEs are also responsible for monitoring products that are manufactured in other countries but are approved for use in the United States as well as initiating airworthiness directives for those products as deemed necessary. The functions of the four Directorates can be details as follows: to draft, coordinate, and issue airworthiness directives based upon the information that is provided by an ACO or Directorate Standards Staff.

The responsibility of the owner of a Type Certificate that has been issued an AD involves:

• Notifying the FAA when they are made aware of any failure malfunction, or defect in any product, part, process, or article manufactured by them.

• Developing appropriate design changes to correct any unsafe condition.

• Incorporating the correction (corrective action) in the future generation of the product that will ensure that the product remains in a safe operating condition.

Aircraft owners as well as operators are responsible for ensuring that they are in compliance with the requirements of all airworthiness directives that apply to their aircraft. Anyone who continues to operate a product that is not in compliance with an applicable AD is in violation of 14 CFR 39.7. In order to locate all applicable ADs, an online search must be conducted for the product, such as for the aircraft, engine(s), propeller, or any other installed appliance. If multiple series are discovered under the aircraft or engine model, it then becomes necessary to also search for ADs that are applicable to the model as well as to the specific series of that model. No person may operate a product to which an AD has been issued except in accordance with the requirements of the AD, and the owner or operator of an aircraft must continue to remain in compliance with all ADs within the compliance time that relates to the effective date of the AD which determines when the actions are required.

Airworthiness directives are constructed in two parts: the preamble and the rule, where the former section provides the basis and the purpose of the AD while the latter section provides the regulatory requirements for correcting the unsafe condition(s). Typically the ADs will include: the description of the unsafe condition; the product to which the AD applies; the required corrective action, operating limitations or both; the AD effective date; a compliance time; the source for additional information; and information regarding alternative methods of compliance with the requirements of the AD. ADs provide a three-part number designator which can be demystified as follows: the first part is the calendar year of issuance; the second part consists of the biweekly period of the year when the number is assigned; and the third part is issued sequentially within each biweekly period. It is important to note that not all ADs necessitate a corrective action; some ADs just include limitations, but each AD is intended to resolve an unsafe condition.

The Federal Register is the official daily publication of the United States government which generates the printed or hard copy method of providing information to the public regarding laws that have been enacted or will be enacted. Electronic versions of the airworthiness directives are available from the Federal Register and from the FAA Regulatory and Guidance Library (RGL). The RGL contains all of ADs which can be searched under the manufacturer, model or AD number itself. Electronic copies of the ADs can be downloaded from the RGL to the computer of the owner or operator, and subscription services are also available via email from the RGL home page. Once a subscription has been activated, any AD that pertains to aircraft and engine makes and models that have been selected, will be emailed as attachments within minutes of the document being posted. The FAA provides the public an opportunity to comment on the notices of proposed rulemaking as well as on final rule ADS that are published without prior notice. They are all published in the Federal Register and include information regarding how to submit comments. The FAA does not request comments regarding Emergency ADs at the time of their issuance although the FAA does request comments when they are published as a final rule AD in the Federal Register.

The standard airworthiness directive process for the three types of ADs (Notice of Proposed Rulemaking or NPRM, which is followed by a Final Rule, Final Rule, Request for Comments and Emergency ADs) adheres to the following procedure: once an unsafe condition is identified, a proposed solution is published as an NPRM, which then solicits public comment on the proposed action. After the comment period concludes, the final rule is generated while considering all substantive comments received, with the rule perhaps being changed as warranted by those comments. The preamble to the final rule AD provides response to the substantive comments or states that there were no comments received. In cases where the critical nature of an unsafe condition warrants the immediate adoption of a rule without prior notice and/or the solicitation of comments (typically in less than 60 days), a finding of impracticability becomes justified for the terminating action which allows it to be issued as an immediately adopted rule which is then published in the Federal Register with a request for comments. The Final Rule AD may be changed later if substantive comments are received. When an Emergency AD is issued, it requires immediate action by the owner or operator since its intent is to rapidly correct an urgent safety of flight situation. An AD is considered to be no longer in effect when it has been superseded by a new AD which states that the previous AD is no longer in effect and that there are no compliance requirements for an AD that has been superseded.

Different approaches or Alternative Methods of Compliance (AMOC) that are not specified in an original airworthiness directive can, with FAA approval, be used to correct an unsafe condition on an aircraft or aircraft product. Although the proposed alternative may not have been known at the time the AD was originally issued, it could be acceptable to accomplish the intent of the original AD. A compliance time that differs from the requirements of the original AD can also be approved if the revised time period provides an acceptable level of safety that equals or exceeds the requirements posted in the original AD. Provisions for an AMOC are desirable from the owner’s or operator’s point of view because it can eliminate the necessity of constant AD revisions when acceptable methods are developed for AD compliance. If an AD does not contain any provision(s) for approving an AMOC, the AD must undergo revisions before compliance can be accomplished by any method other than what is stated in the original AD. Each AD states which office within the FAA Aircraft Certification Service that is responsible for that particular AD. An AMOC can be approved by the manager of the office that is responsible for that specific AD including different compliance times for the requirements of a specific AD. One FAA Aircraft Certification Office will have responsibility for AMOC approvals for products manufactured within the United States while a product manufactured outside of the United States will be under the jurisdiction of a Standards Staff branch office of one of the four FAA Aircraft Certification Directorates.

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Dr. Mary Ann O’Grady

The aircraft annual inspection that is required by the Federal Aviation Administration is a straightforward process that is not difficult to conduct. However, difficulties can arise when the mechanic that is hired to perform the aircraft annual inspection is neither familiar with the process nor capable of keeping track of the time and materials. So, it is the responsibility of the aircraft owner to research the experience of the mechanic with his or her particular airplane, since the annual inspection is certainly not the time for on-the-job-training on the part of the mechanic.

In addition to determining the mechanic’s proficiency with performing annual inspections, it is also the aircraft owner’s responsibility to locate a qualified shop that is equipped with all the special tools and equipment to conduct the annual inspection properly. For example, are the tools well organized, and are stickers readily apparent to validate that the shop’s equipment has been calibrated and will test according to current tech data? The employees working in a qualified shop have been trained much more than just the bare minimum to attain an A&P license, although lesser-experienced mechanics may be working under the guidance of a senior mechanic with advanced training and many years of experience. Well-qualified shops should demonstrate a high degree of organization with the use of a tracking system that not only tracks the job and what parts were required, but also which mechanic(s) worked on the job and for how long. This can be accomplished with a scanner to ensure that the customer is only charged for the work that was done and the actual time and materials that it took to do it. The treatment of the aircraft, including its parts, is also an important consideration with regard to where it / they will be stored before and after the aircraft annual inspection, as well as where it will be parked if it is awaiting new parts.

The inspection guidelines dictate that the aircraft owner should have a record or inventory that identifies just what was given to the shop, and copies made of the most important documentation, such as previous log entries for past years detailing major repairs, tach and total time as well as AD note compliance, modifications and alterations, and 337 forms. Disorganized record-keeping can result in significant delays and greater financial expense since the shop is required to list in the aircraft records any maintenance, all repairs, inspections, and the results and AD notes that were complied with. The shop can only return the aircraft and associated prop, engine, etc. to service if there are no outstanding AD notes due at the time they completed the inspection.

The pre-inspection phase of the aircraft annual inspection determines that the aircraft meets the type certificate design or original configuration and that it is in safe operating condition, which is governed by various approved data including aircraft maintenance manuals, AC-43 13-1b, AD notes, and service bulletins. However, the FARs specify exactly what must be done during the annual inspection via a checklist, and the items that are to be inspected are listed under FAR Part 43, Appendix D.

The preparation for inspection and the inspection itself is divided into separate parts since repairs are accomplished only after the inspection has been completed, all the AD notes have been researched and a determination made regarding what applies and ultimately what needs to be done. To avoid conflict between the aircraft owner and the shop conducting the inspection, the inspection should be treated as a separate entity without including servicing, lubrication, repairs or AD note compliance. The cost of the inspection including labor and materials should be clearly communicated to the aircraft owner so that he or she is aware that any repairs, AD note compliance, parts, alterations, fluids and hardware are additional charges.

Once the inspection has been completed, a list should be constructed identifying each deficiency that was found and whether the repair should be classified as “required” or “just a good idea.” It is important that the inspection be completed prior to discussing repairs, and a determination made that pertains to the airworthiness of the aircraft – did it pass inspection or not? If it did not pass, a discrepancy list must be provided to the owner, and the inspection categorized as “un-airworthy” in the aircraft records. If the owner disagrees with that inspection designation or wants another shop to conduct the repairs, he or she may choose another facility depending upon the required repairs. Once the required repairs are completed, the aircraft does not require re-inspection, and the annual inspection date remains in effect requiring another inspection 12 calendar months after the previous inspection.

Pre-Inspection Details

Usually, the first step in a pre-inspection is the walk-around, which is similar to the pre-flight, to identify any previous damage as well as to note of the general condition of the aircraft, such as strut inflation, flap, rudder and aileron position and condition as related to the cockpit indication. The fluids (oil and fuel) are also examined for leakage or puddling, and the engine is checked for oil level, missing parts, baffles, cowling damage, missing fasteners, etc. The aircraft is then operated with a taxi check to determine the proper function of the instruments including gyros, compass, autopilot, radios, brakes, etc., and a written record is constructed. At the time of the run-up, the readings of all instruments before, during and after the run-up are recorded including a static power check using a calibrated RPM instrument which is mandatory as part of the aircraft annual inspection. This detailed record should be kept with the aircraft inspection data for future comparison.

During the actual inspection phase, the inspection panels are removed by anyone including the airplane owner, and the inspection should begin with an oil drain, a portion of which should be collected for analysis, removing the suction screen (if removable), the oil filter and/or the pressure screen to properly check for contamination. While the engine is warm, the spark plugs, either upper or lower, are removed and a compression check computed, after which the results are written on paper rather than on the cylinder. If one or more cylinders indicate low compression or a significant amount of metal particles in the oil, sump screen or filter media there is no point in conducting an in-depth inspection of the engine. If the engine compression is fine, and there is a negligible amount of metal apparent, the inspection continues at which point the inspection panels, seats, carpeting, battery, etc. are removed. Mechanics should report their observations of stripped screws, broken wires, etc. as well as to hang a bright colored streamer from each area that needs attention prior to reassembly. Mechanics should remove the wheels and service the wheel bearings; mufflers are also removed and checked for leakage with a test unit, and any discrepancies are noted in writing.

When the airplane is ready for the actual inspection, the shop inspector is contacted so that he or she can review the AD notes and log books for compliance as well as to review the recent mechanic’s notes recorded in the current pre-inspection phase. The shop inspector then records all of his or her findings, and when this inspection has concluded, he or she will inform the mechanic, what, if any, part of the aircraft can be reassembled. Any areas that require repair will be left open or accessible, and a complete list will be compiled with a written estimate for the necessary repairs as well as for the repairs that can be deferred.

The aircraft owner is contacted and notified prior to any repairs being made, but it is important that all necessary repairs be disclosed by the mechanic whether or not that shop is capable of making the major repairs. Owners are often distressed when an inspection reveals unanticipated or more extensive damage than initially thought to exist, but it is not the inspector’s fault that further damage was identified suggesting a “don’t-shoot-the-messenger” scenario. When the aircraft annual inspection is signed off, it is stipulating that the entire airplane has been found to be airworthy and safe to fly, so there is no such thing as “good enough” to return to service if the inspector is willing to affix his or her signature to the inspection report.

Repairs are another phase that follows the completed aircraft annual inspection, but they are becoming more difficult as parts continue to increase in price and decrease in availability. Competent shops are always searching for ways in which repairs can be made more economically by checking for all options that may be available to complete the job correctly the first time, thereby guaranteeing the airworthiness of the airplane.

Get Started With Your Flight Training Today

You can get started today by filling out our online application. If you would like more information, you can call us at (844) 435-9338, or click here to start a live chat with us.

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