A Personal MEL

A list for effectively using your airplane while maximizing safety

March 1, 2005

One of the common threads in aviation — general aviation, the airlines, corporate, the military, and even the space program — is the problem of dealing with something on the aircraft that is broken. Hardly a student or a renter has not had to deal with an airplane that has a broken part. It might be something that is fairly minor, but annoying, such as an instrument panel light, or it might be something much more important, such as the oil pressure gauge.

If you have ever flown on an airliner, the odds are that something on such a big piece of machinery was not in total working order. You want an item of severe inconvenience? Try operating a three-hour flight with the only lavatory on board not available for passenger use. Is it worth canceling a flight just because the toilet doesn't work, or is it a better alternative to alert the passengers to the problem, then give them the option to take that flight or wait until a later one? The latter is a less expensive alternative while at the same time allowing the company to get the airplane to a maintenance facility where repairs can be made.

The airlines and private turbine aircraft owners operate with something called a minimum equipment list (MEL). In plain English, the MEL is a legal FAA-approved document that allows companies or individuals to operate their aircraft with certain equipment not working. When the aircraft is certified, the MEL is drafted, often by a committee consisting of the manufacturer, the users, and the FAA.

When something on the airplane that is normally required by the federal aviation regulations — one of the fuel gauges, for example — stops working, the MEL will state how many total fuel gauges are installed, how many must be working at the time of dispatch, and any operational procedures that must be followed. In the case of an inoperative fuel gauge, there will be a procedure stated to manually verify the fuel quantity on board prior to departure. If all of the conditions can be met, then the repair will be deferred. To defer something means that once a discrepancy is noted in the on-board maintenance log it can be left as is without repair for a defined period of time. When that time has expired, the affected item must be fixed in accordance with approved procedures.

What happens if something breaks that is nondeferrable? Two examples on an airliner are the cabin pressurization system and an engine failure. If an engine quits working, the airplane is grounded until the problem is fixed, even if the airplane is a Boeing 747 with four engines. That's pretty obvious. If the pressurization system fails, a provision usually exists to be able to ferry the airplane, without passengers, to a point where repairs can be made. Only then can the airplane be put back into revenue service.

So how does all of this pertain to the average pilot in his personal airplane or in a rental? The average Cessna, Beech, or Piper does not have an MEL. It is up to the pilot/owner to decide which items justify grounding an airplane until repairs can be made. How about that fuel gauge mentioned above? Generally speaking, fuel gauges are required equipment. The airlines, however, often have exceptions. On the Canadair Regional Jet at my company, there are quantity readouts for the two main tanks, the center tank, and a fuel total. If one readout is broken, we can follow manufacturer- and FAA-prescribed procedures, in coordination with our maintenance department, to operate for a limited period of time with one readout inoperable. GA pilots don't have such freedoms with FAR-required equipment. Similar procedures are used for burned-out bulbs in the nav lights. While nav lights are required, can you imagine the cost of canceling a daytime flight for a dead $5 light bulb? The pilot's operating handbook (POH) may or may not offer any guidance on a particular system. You could talk to a mechanic and get his opinion. The owner of the flight school may tell you that it's OK, but that is a bit of a biased opinion, especially if another airplane is not available for you to rent.

If you fly regularly, either as a renter or an owner, an interesting exercise would be to sit down with the POH and the list of equipment installed in your airplane and decide, in your mind, which items are deferrable, and if they are, under what conditions. Most flight schools have some sort of in-house policies on most of their equipment. Such policies may or may not be written down, and are usually borne of past experience. When I was a full-time instructor, we had some limitations on what equipment repairs could be deferred for a student-flown operation, for rated private pilots, and for experienced instrument pilots. For student pilots flying solo, the airplane had to be in pretty sound condition. If the attitude indicator failed, only instructors were approved to fly the airplane to a repair facility, and then only in good VFR conditions.

Most of the equipment in a common single-engine airplane should be fairly easy to make a decision about. Landing light is out? Don't fly at night. Radios are inoperative? Day VFR only in a nontowered environment. Sometimes, though, when a flight is important, the decision can be more difficult. It's much easier to deal with such a scenario if you have thought it out ahead of time, away from the immediate pressure of a flight. What if the airplane does not have GPS and the VORs don't work? Are you comfortable dead reckoning for the duration of the flight? Are you that confident in a forecast for clear weather? The last thing any pilot should do is make a decision that impacts the potential safety of flight based on external pressures such as passengers or an impending meeting.

Make your decisions in the comfort of your living room, with the time to think through the pros and cons of each alternative. Study the manual — systems knowledge is important here — and derive as much information as you can. Study the emergency checklists, and see what types of scenarios the manufacturer considers an emergency. Did you miss something? Talk to a mechanic and to more experienced pilots, and see what they would do in various scenarios.

The point of this discussion is not to condone flying an airplane that is not in full working order. Rather, you need to know what your comfort level is if something should stop working in the worst-case scenario in which you fly. For example, if you are strictly a day-VFR-only pilot flying in the late afternoon when the VOR in your airplane fails, your personal decision might be to land at the nearest suitable airport and try to arrange for repairs either that day or the next morning. If you take the time to establish this personal policy ahead of time, before the situation develops, it's much easier than trying not to rationalize flying an airplane that does not meet your comfort level. If you fly enough, you will eventually have an in-flight mechanical problem. Take it from me that having a plan ahead of time is much easier on the mind.

One of the checks and balances of an FAA-approved MEL is that it takes the pressure off both the company and the pilot, because the procedures are cast in stone, and because they were established before they were faced in daily operations. While your personal MEL may not be submitted to the FAA for approval, it will be submitted to you. You should be comfortable with it, and once you create it, you should stick with it, changing it only as your experience grows or your equipment improves. Properly utilized, it will enhance not only your personal safety and comfort, but also help you achieve the proper balance between effectively using your airplane and your pilot certificate with maximizing safety. It may mean leaving an airplane at a strange airport for longer than you would like, but better safe and personally comfortable than regretful.


Chip Wright, AOPA 1086994, of Hebron, Kentucky, is a CRJ captain for Comair.


Inoperative Equipment

Many pilots are unaware of the very stringent requirements of FAR 91.213 (see " Pilot Counsel: Inoperative Equipment," October 1995 Pilot). FAR 91.213 states that "no person may take off an aircraft with inoperative instruments or equipment installed." That means any instrument or piece of equipment, whether important to the flight or not.

The alternative to the minimum-equipment-list concept is contained in subsection (d) of FAR 91.213. Essentially it involves placarding, plus deactivation or removal of the inoperative component.

This alternative is available for most general aviation aircraft. It is not available for any turbine-powered airplanes.

Subsection (d) places responsibility squarely on the pilot. In the most general terms, FAR 91.213(d) requires that the pilot first make a determination that the inoperative instrument or equipment does not constitute a hazard to the aircraft.

Then a determination must be made by the owner or operator (who doesn't necessarily need to be a certificated pilot) that the inoperative instrument or equipment is not excepted by FAR 91.213 (d)(2). The owner or operator must determine that the inoperative instrument or equipment is not "part of the VFR-day type certification instruments and equipment prescribed in the applicable airworthiness regulations under which the aircraft was type certificated."

The other determinations are somewhat easier. One requires resorting to the aircraft's approved flight manual or pilot's operating handbook (POH). The inoperative instrument or equipment must not be required by the aircraft's equipment list. Another requires resorting to the operating limitations section of the POH where there should be a "kinds-of-operations equipment list" that must list and identify the installed equipment that affects any operating limitation (such as VFR, IFR, day, or night). The inoperative instrument or equipment must not appear on this list for the operation intended.

The inoperative instrument or equipment must not be required by FAR 91.205 for the specific kind of flight operation intended (e.g., VFR day, VFR night, high altitude, or Category II operations). Nor can an airworthiness directive require it to be operable.

After ensuring that an inoperative instrument or piece of equipment is not required, then the inoperative device must be deactivated or removed. If it is deactivated, it must be placarded "inoperative."

If an instrument or piece of equipment is removed, then the cockpit control must be placarded and the removal recorded in the maintenance record for the aircraft. — AOPA Government and Technical Affairs staff