U.S. Department
of Transportation

Federal Aviation

St. Louis
Flight Standards District Office

10801 Pear Tree Lane
Suite 200
St. Ann, Missouri 63074


November 2004 




Thought for the month..... If everybody is in charge then nobody is in charge…

Aging Aircraft... Is your airplane more than 25 years old? Do you ever talk to friends, who don't fly, about how safe your old airplane is? Maybe you're in the business of inspecting and maintaining airplanes and your friends look to as an expert on the subject of aviation safety. Have you ever heard them ask, "How safe can an airplane that old be"? Did you respond with a chuckle like many of us do and say that all airplanes are required to have an annual inspection and that is what keeps them safe and flying? Really?

In 2000 the average age of single-engine airplanes in the U.S. was more than 30 years old. At that rate by the year 2020' unless there is a large influx of new airplanes' that average will be approaching 50 years. This fleet of single-engine and small twin-engine airplanes were not designed with the idea that they would be in service that long. With continued updates and improvements in avionics these airplanes will remain in service well beyond anything the airplane manufacturers considered when they were designed. Back in 1980, the FAA incorporated a rule change that required transport category aircraft manufacturers to include instructions for continued airworthiness on the aircraft they build. That rule required manufacturers to develop a structural inspection program for their products. There is no such rule at this time for aircraft manufactured and certified under Part 23 which most of the general aviation fleet falls under.

A notable age related incident happened in 1988 to an airline located in Hawaii on one of their Boeing 737's. A section of the fuselage ripped open at a row of rivets along a lap joint while the airplane was in flight. Granted, there is a large difference in pressurized vs. nonpressurized aircraft when considering continued airworthiness inspections. But, even nonpressurized aircraft have age-related airworthiness issues showing up. After that incident, the transport category aircraft manufacturing industry and the FAA conducted a study on the effects of age-related conditions. Several airplanes identified by manufacturers and models were singled out for special maintenance program requirements and these requirements were then codified in the Federal Aviation Regulations.

The minimum requirement for inspections that the typical general aviation aircraft is subject to is found in Appendix D of Part 43. This Appendix identifies the areas of the aircraft and components that are supposed to be inspected but does not stipulate the standard. The standard that an aircraft is to be inspected to is found in §43.15. That regulation says the inspector must determine that the aircraft or component(s) "…[meet] all applicable airworthiness requirements". Some manufacturers of older aircraft barely published repair data let alone any limits of airworthiness. Without published limits airworthiness is a judgment call of the inspector based on industry practice and his/her experience. Inspectors have to work out their own criteria for inspection pass/fail criteria. For the most part they do a pretty good job. That is until you end up with one of those "$3000 annual inspections". Then you have the dilemma of trying to guess if this inspector over did the inspection or if the last inspector under inspected the airplane. With this method of determining airworthiness the standard that the inspector uses in the inspection process is as varied as the number of inspectors there are. It has to make you wonder just who is in charge here.

In September 2003 a team made up of general aviation aircraft manufacturers, aircraft owners, representative organizations, and the FAA collaboratively wrote a guide to assist the aircraft inspector and owner in establishing inspection criteria on aging aircraft. That guide is titled "Best Practices Guide for Maintaining Aging General Aviation Airplanes". These guides are available on line at the following websites:

Upcoming Events

November 2
Shoney's Restaurant
Rolla, MO
Aeronautical Decsion Making
6:30 to 9 P.M

December 4
Skyline Aeronautics
Spirit of St. Louis Airport
Midair Collision Avoidance
9 A.M. to 12 P.M.

December 11
Southwest Illinois College
Granite City Campus
IFR/VFR/ Refresher and Companion/Maintenance Seminar
9 A.M. to 4 P.M.

January 6
Wicks Hangar
Shafer Metro East Airport
St. Jacob, IL.
Sport Pilot/Light Sport Aircraft.
7 to 9 P.M.

January 22
Linn State Technical College
Linn, MO 9 A.M. to 12 P.M.
McDonnell-Douglas Green Aviation Building
Sport Pilot/Light Sport Aircraft

Register at http//faasafety.gov for E-mail notification of safety seminars in the St. Louis District.

Good Maintenance is no accident
Steven Long
Airworthiness Safety Program Manager
1-800-322-8876 ext 4830