The Different Pilot Licenses Explained
by Ralph Wetterhahn
Private pilots tend to think that preventive maintenance is a mechanic's job, something they need not worry about. But you, not the mechanic, fly the aircraft, and your life might depend on prevention. As a pilot myself, I’m unwavering in my opinion that good pre- and post-flight inspections are just the beginning. And don’t worry—you’ve got plenty of guidance available to you via a mere online search. If you’re feeling overwhelmed, several online resources provide an excellent primer for pre-flight inspections, for example this pre-flight inspection from the Experimental Aircraft Info website.
What Pilots Can and Can’t Do
While the 100-hour and annual inspections can only be signed off and conducted by a certified mechanic, a major misconception is that these are all that matters when it comes to preventative maintenance. But the primary purpose of maintenance inspections is to look for failure indicators such as deteriorated windows and windscreens, cracked engine cowls, etc. There are many of these things a pilot can and should check before these inspections are due. Part 43 of the Federal Aviation Regulations refers to 31 allowable pilot actions as preventive maintenance, stating in 43.3 (g):
"(T)he holder of a pilot certificate issued under part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under part 121, 129, or 135 of this chapter. The holder of a sport pilot certificate may perform preventive maintenance on an aircraft owned or operated by that pilot and issued a special airworthiness certificate in the light-sport category.
Yes, yes—but what does all this technical language mean? Basically, this regulation allows pilots a number of privileges involving aircraft preventive maintenance. These privileges are spelled out in Part 43, Appendix A. They range from changing oil to performing small fabric patches, changing tires, repainting aircraft, updating GPS databases and replacing prefabricated fuel lines. If you’re a pilot, you should read this particular section closely to discover what you can and can’t do. You must have at least a private pilot certificate and be the registered owner (including co-owners) of the affected aircraft and be signed off by a Certified Flight Instructor.
Preparing Aircraft for Inspection
You can also prepare your aircraft for inspection. The time investment for an annual inspection ranges from six to eight hours for a two-seat, light aircraft like a Cessna 152, and up to 40 hours for complex, twin turboprops such as a Beech King Air 200. Removing and installing panels doesn’t require skills specific to an A&P mechanic. Opening panels prior to an inspection is A-OK, but requires the ability to remove and install fasteners and keep track of the removed hardware. Pilots and owners can accomplish these tasks and save money, even on the smallest of annual inspections.
Failure to Maintain Can Be Deadly
A fighter pilot friend of mine loved to fly, so while he was desk-bound at the Pentagon, he used his commercial pilot's license to tow gliders aloft on weekends. The chore required full power all the way to release altitude, then a quick return to the runway for the next tow. On descent, pulling the engine to idle would cool the engine too fast, putting it in high stress. Instead, he would descend using steep turns and g-forces to keep the airspeed down while slowly reducing power until the flare for landing. The combination of abnormal airframe and powerplant stress called for increased attention to preventive maintenance, such as more frequent inspection of major structural components by both maintainers and pilots.
My friend was unable to attend any of the required inspections due to his day job. But his knowledge of high-performance aircraft should have led him to look during preflight for signs of overstress, such as wing ripples, surface corrosion and the kind of permanent deformation that would have alerted him to potential danger. Sadly, he invited a bystander to join him on a tow one Sunday. That additional 120 pounds meant over 300 pounds of stress during the 3-G descent, enough to cause the left wing to fail. The result was fatal. A follow-up Investigation showed extensive corrosion of the main spar and wing supports.
This example shows how airframe knowledge beyond typical pilot know-how could have given enormous benefits to a pilot wanting to fly safely. Understanding the principles behind the stressful operation of an aircraft can give unique insight into potentially dangerous situations and allow proper prevention. Engaging in aircraft preventive maintenance can often mean the difference between life and death.