Building basics: Bare Minimums

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building basics

Bare Minimums Using aircraft equipment lists to keep the airplane airworthy Greg Laslo aircraft’s operational life. What if one of those nifty-neato gadgets breaks? What kind of hardware failures, if any, are enough to ground the aircraft you’ve worked so hard to build?

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ou’ve installed a gee-whiz your Technical Counselor and Flight array of all the latest equip- Advisor, and you’re about to make ment on your new homebuilt, aviation history. and you’re about to make your But there’s something else you first flight. You’ve got your plan, might want to think about—not you’ve reviewed AC 90-89A with just now, but throughout the

Commercial aircraft operators and production aircraft manufacturers include equipment lists in their aircraft manuals that help the pilot decide exactly that. It’s worth considering, if only because it can save you time flipping through your latest copy of FAR 91. There are two kinds of equipment lists you hear mentioned in the aviation world: the minimum equipment list (MEL) and the “required” equipment list. The MEL is a formal FAA-approved, legal document based on a Master Minimum Equipment List (MMEL) that’s issued to the operator of a specific airplane along with a letter of authorization from the friendly FAA aircraft inspector. It’s required by FAR 91.213 for some types of operations, and essentially says that a typical airplane includes a complement of redundant systems, including instruments, navigation radios and indicators, and “comfort” items. If one or two of those pieces of equipment go toes-up, say, the No. 2 VOR or the passenger reading lamp, the aircraft will still be safe to operate under certain circumstances, although not necessarily revenue-generating flights. Mostly, it establishes procedures that allow the flight crew to continue flying long enough to get the item fixed. Given that “working girl” stipulation, your homebuilt aircraft, like most nonturbine, single-engine production aircraft, doesn’t need an MEL. In most cases an MMEL for those airplanes doesn’t even exist unless it is used for Part 121 airline or Part 135 air taxi operations. Can you seat a fare-paying passenger in a seat without a functioning seatbelt? Check the MEL. The list that comes with modern privately operated production aircraft is published in the Pilot Operating Handbook or Airplane Flight Manual and is specific to that aircraft—that is, it includes everything the factory installed in that specific aircraft, including speEAA Sport Aviation


So, what do these lists, which clearly have nothing to do with homebuilt aircraft, have to do with homebuilt aircraft? cial items the customer requests. Consequently, it’s an encyclopedic list of all the accessories and instruments installed on your

standard-category production aircraft, such as: seat, front (2); radio, navigation (2); propeller, fixed pitch (1), carpet, flame retardant (1). It notes the “required equipment” necessary for flight, based on the FARs. Want to know if you can fly without a prop spinner on your Cessna 172? Check the required equipment list. Both lists are the result of the great minds back at the factory and the local Flight Standards District

Jean Batten, 1934

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building basics Office (FSDO) coming together to decide what, exactly, comprises an unairworthy aircraft. So, what do these lists, which clearly have nothing to do with homebuilt aircraft, have to do with homebuilt aircraft? As luck would have it, there are a few things these lists of “thou shalt nots” can do for homebuilt

pilots. All you’ve got to do to get started is make a list of everything you’ve bolted, riveted, or plugged into your airplane, then figure out how important the FAA thinks each item is. There’s no need to present this list during inspection; it’s only for your use, mostly in the name of safety and quick reference.

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FAR Requirements The FAA provides a guidance to help you figure out what your airplane needs and what it can do without in FAR 91.205. Say, on preflight one day, you notice that the “light, anti-collision, white (2)” are not flashing. Is it legal to fly on a severe-clear VFR day? Because you’ve compiled your list, you can flip to the “Lights” section to look up the item. As it turns out, if you’ve got ’em, you’ve got to use ’em, unless using them represents a hazard (that is, a hazard greater than you getting popped for flying with inoperative anti-collision lights). Now, if the “light, position (2)” weren’t working, you could still fly, right up until dark, though that’s a slim consolation now. Likewise, other lights—including cockpit, panel, landing, and taxi lights— have operational requirements of their own that you’ll want to document, which change with the time of day, the weather conditions, and the nature of the flight. A generic single-engine MMEL is likely available at your local FSDO’s website if you’re curious to see what this list looks like. Mostly, it’s a list of equipment, plus a maintenance schedule, and a description of when the item is needed and how to get around it when it’s not working. The first thing you’ll note is that the list includes equipment you probably don’t have installed, such as Traffic Collision Avoidance Systems (TCAS), air conditioning, coffee makers, fire suppression systems. After you get over that shock, focus on the equipment that is installed on your airplane. You’ll get tips for when to call it quits, and when it’s “safe” to proceed on your merry way.

Broken Components If you can’t fly with in-op lights, what about other components, such as cockpit instruments? And what do you do if one of those is 82


kaput? Again, FAR 91.205 offers guidance. First off, if it’s one of the primary instruments required for day VFR, and it’s Tango Uniform, you’re up a creek. That includes the airspeed indicator, altimeter, compass, tachometer, oil pressure gauge, temperature gauge, fuel gauge, seat belts, an emergency locator transmitter (if required by FAR 91.207), emergency signal flares (if the flight’s over water), and landing gear position indicator (in a retractable-gear airplane). Planning to fly at night? You’ll also need those position lights, a spare set of fuses, and an adequate source of power to light up everything. Interestingly enough, a landing light is only required if you fly for hire, and pitot heat, alternate air source, and a vacuum gauge or ammeter/voltmeter aren’t required at all. Think about that the next time you think the regulations are too strict. For instrument flight, you’ll need several more pieces of equipment, including a gyroscopic rateof-turn indicator, a slip-skid indicator, a sensitive altimeter adjustable for barometric pressure, a clock, an artificial horizon, a generator or alternator, a directional gyro, and a two-way radio and navigation instruments. That last part is where your personal equipment list will come in handy, if only to remind you of the kinds of approaches you can fly with a placarded nav instrument. For instance, if your VOR receiver is out of service, you can fly NDB or, if properly equipped, a GPS approach. Note that you can’t launch on an IFR flight plan with only a GPS for navigation, even if it’s certified for IFR operations. And if your clock’s shot craps, you’ll want to know that you can substitute a watch. But what about a malfunctioning electric trim-tab switch? If the elevator tab can be repositioned into the neutral position, should you still be able to operate the airplane? That’s a EAA Sport Aviation


good question for your Technical Counselor, inspector, or mechanic. Same with all those other niceties you’ve installed, such as door locks, fire extinguishers, and autopilots.

Time to Repair Speaking of placards, owners of production aircraft are required to remove or disable and placard

components that aren’t functional so a forgetful pilot isn’t tripped up. That would be you, so judge accordingly when it comes to placarding your own aircraft. An MEL requires an operator to replace or repair inoperative components within an agreed-upon time period, which is described within the document— immediately for some items, up

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to 72 hours from the “day of discovery” for others, and at the next inspection for less-significant parts. Obviously, some things need to be repaired sooner than others. Use your judgment—and that of your Technical Counselor or mechanic. After all, you wanted an operational instrument there for a reason, and you’re the one who has to declare the aircraft airworthy or not. And while you can remove the passenger seatbelt from your aircraft—assuming no one was planning on sitting there—without affecting your weight and balance, other components have mass about them, and removing them could tweak your calculations. Consequently, you might want to note weights and moment arms of each component. Remember, though, that the FAA makes a distinction between major and minor alternations in FAR 21.93. A “minor” change has no appreciable effect on the maximum weight, center of gravity limits, structural strength, or operational characteristics of the aircraft. Anything else, such as propeller, engine, covering, and control surfaces, are “major” changes—see FAR 43’s Appendix A—and the removal or addition will have to be reported to the FSDO. Then again, most major alternations won’t inspire you to go flying immediately anyway. Remember, FAR 91.213(d) says you don’t need a minimum equipment list; you’re just using it as a reference to help you decide when your airplane is safe to fly. If something breaks, and you’re still legal to fly, per FAR 91.205, all you’ve got to do is disable and placard the nonfunctional item. If you have any questions, your Technical Counselor or an A&P mechanic can help fill in the blanks. Over time, components break. It’s up to you to decide whether your aircraft is fit to fly when that day comes.