The following report was copied from the Aviation Consumer used airplane guide printed in 1989. The prices in this edition are out of date of course.

If you drive an old MG or Austin Healey, you might be the sort to fly an AA-1. The sprightly two-placer built originally by American Aviation and then Grumman American, and officially known by a variety of names but usually referred to as the Yankee richly deserves the cliched label of "sports car of the air."

In the tradition of the post-war British sports cars, it is small, simple, quick handling, noisy, idiosyncratic and tremendous fun for the stout of heart. But be careful. The AA-1 has a terrible accident record, particularly in the hands of pilots transitioning from other models. It's twitchy on the controls, sinks like a brick at low speeds and is dangerously lacking in climb performance under heavy, hot and/or high conditions.

On the plus side, an energetic owners' group, the American Yankee Assn., provides cut-rate insurance, plus advice on how to handle the AA-1's idiosyncrasies both in the air and the maintenance shop.

Genealogy

The AA-1 series was born in the mid-I 960s as the BD-1, the first airplane designed by Jim Bede, the loquacious designer/promoter who later became notorious for his ill-fated BD-5. The BD-1 was Bede's notion of a cheap airplane for the common man, small enough to fit into a garage (with folding wings) and using interchangeable parts to keep costs down. Bede managed to raise money to build a prototype, but the company ran into financial turbulence and Bede was kicked out in 1965. The company was reorganized as American Aviation, and the BD-1 was greatly modified (no more folding wings) and eventually certified as the AA-1 in 1967.

It first appeared on the marketplace in 1969. Named the Yankee Clipper, the first AA-1 was a sporty, responsive little hot-rod with a rakish slide-back canopy and superb visibility. The Yankee won many admirers for its snappy flying characteristics, but it had a rather violent stall and a severe tendency to "get behind the power curve" - i.e., a rapid buildup of induced drag at low speeds.

Image Alteration

In an attempt to change the Yankee's image from that of a hot sports plane to a flight school aircraft, an additional model was introduced in 1971 the AA-1A Trainer, with the wing leading edge redesigned to improve stall and induced drag characteristics. The "hot-wing" Yankee was discontinued in 1972 after a production run of 459 aircraft. Soon thereafter, American Aviation was bought by Grumman and became Grumman American. In 1973 the AA-1A became the AA-lB, with gross weight upped from 1,500 pounds to 1,560. Two versions were available: a basic flight school training model with a climb prop, and a fancy sport" version called the TR-2 (talk about your sports cars of the air!) with a cruise prop for better top speed.

More Power

A big change came in 1977 with the AA-1C. The Lycoming 0-235 was revved up to increase horsepower from 108 to 115, and gross weight was boosted to 1,600 pounds. A new Sensenich prop increased thrust, and the size of the horizontal stabilizer was increased to improve the airplane's marginal pitch stability. The trainer version of the AA-1C was called the T-Cat, while the sporty version was called the Lynx. Production was halted after 1978 due to falling sales of only 88 that year, compared to the 200-plus annual sales figures chalked up during the early 1970s. (Meanwhile, the rest of the industry saw sales soar to record levels that year.) A total of 1,774 AA-ls was built.

Used Plane Market

An estimated 1,200 of the AA-1 series (for convenience' sake, we'll call them all Yankees) are flying today, and they are generally undervalued in the current strong used plane market. A careful shopper can get a real bargain. The used Yankee market is basically divided into three tiers: the stock AA-1, -A and -B models at the bottom; the stock -C models in the middle, and the modified airplanes with big engines at the top. Typical price for stock AA-1, -A and -B aircraft in decent shape is $7,000-$8,000 or so, according to David Fletcher, a Yankee enthusiast and Houston aircraft broker. A barely flyable dog can be had for as little as $5,000 (think of it, an airplane for the price of a Yugo!), while a clean, low-time aircraft will command up to $9,000. A -C model, with its more powerful engine and smoother pitch control, averages around $11,000 for a decent mid-time airplane, with the dog/cream-puff range at about $8,000-12,000, according to Fletcher.

Don Andrew, a partner in Air Mods NW, a Statelier mod shop specializing in the AA-1 and AA-5 series aircraft, reports higher prices in his area. The minimum for an AA-1 there is about $7,500, with a maximum of $11,000 or so for the -1 and -A models and $12,000 for a -B. Andrew sets the price range for the -C at $9,500 to $13,000, with $11,000 typical for a mid timer.

AA-1s tend to get souped-up with 15O-hp engines, long-range tanks, speed fairings, fancy panels and paint jobs and other expensive mods, and these aircraft can be worth a lot more. Fletcher knows of a 1969 Yankee Clipper with a 150-hp engine that recently sold for $18,000, and a hopped-up -C model can be worth even more.

Performance

In terms of cruise speed, the AA-1 is the class of its class. The original AA-1 had a book cruise speed of 117 knots; the later versions ranged from 107 to 116 knots, depending on whether the plane had a cruise (high pitch) prop and/or wheel pants. Its main competition, the Cessna 150, listed at 100 knots, and even more recent two-seaters like the Piper Tomahawk and Beech Skipper fall well short of the AA-1. Yankee owners tell us that the airplane delivers pretty close to book numbers; the typical AA-1 gets an honest 113-117 knots at 7,000 feet and 75 percent power, burning seven gph, according to Ken Blackman, a long-time Yankee guru and partner in Air Mods NW. That's a good 17 knots faster than the other two-seaters. (We recall a Grumman American sales demo flight a few years ago during which an AA-1B blew by a C-150 by a good margin in a side-by-side flyoff) At more modest power settings, you'll get 109 knots on six gph, according to Blackman, and that's the speed range reported by most owners. The AA-1's speed advantage should be no surprise; it's a tiny plane, with short wings and about 15 percent less wetted area than the competition. The bonded skin surfaces are rivet-free, which helps cut parasite drag.

Climb Problems

Climb performance is another story. The book says that climb performance is comparable to other two-seat trainers, but the book is wrong. At light weights, or in cold weather, the AA-1 climbs well enough, but load it to gross, throw in a hot day and a high field elevation, and you've got trouble-- induced drag builds up rapidly at higher angles of attack, and climb performance decays at an astonishing rate -particularly in the original "hot wing" Yankee. Comments one owner, "With density altitudes over 5,000 feet, I do not recommend gross weight." Even the factory test pilots couldn't hide this unfortunate characteristic completely; the AA-1's service ceiling is only 11,000 feet, compared to 12,000 to 15,000 for the various 150 models. Book takeoff performance is adequate, but once again, the book lies when it comes to hot weather or high field elevations Says Mike Antoniou, one of the original factory test pilots, "The induced drag is so high that the "bucket" of the- power-required curve-the speed at which the airplane flies on the minimum amount of power occurs at a high airspeed, around 80 mph. "The problem is that the owner's manual tells you to rotate on takeoff at 60-65 mph. That means you're leaving the ground well on the back side of the power-required curve. At heavy weights, you are depending on ground effect for acceleration, and there are certain wind conditions where ground effect is substantially reduced. I seriously doubt that a grossed out AA-1 can make it out of ground effect at 65 mph at moderate density altitudes."

The climb problem is exacerbated by the speed hungry factory's propensity to use high pitch cruise props, which boosted cruise speed a few knots, but degraded climb power. "That cruise prop is a joke," commented one former Grumman American dealer. "I don't know how they ever got it certified." The Sensenich prop on the AA-1C, on the other hand, improves climb performance noticeably.

Accident Payoff

The AA-1's poor climb performance is reflected in the accident statistics; there is a high incidence of crashes in which the airplane fails to clear an obstacle (More details on this in the Safety section.) The lesson is clear: The AA-1 is a ground lover that should be flown with great care with two people aboard. Ironically, one way to improve runway performance is to completely ignore the pilot's operating handbook (which calls for flaps-up takeoffs) and deploy one third to one-half flaps. Climb rate is about the same, but climb angle improves markedly. "I always teach people to use partial flaps for takeoff," says Blackman. Comments test pilot Antoniou, "Yes, our test data did show takeoff performance to be improved with flaps. My guess is the sales department didn't want people to think that the plane was so "hot" that it required special flap manipulation for takeoff. Remember, it was supposed to be a trainer."

Landing performance is excellent, however, due to the high sink rate available. Even though the AA-1 has small, marginally effective flaps and an approach speed 10-15 mph higher than a Cessna 150's, it can come close to matching the 150's landing performance. (Just be careful taking off again.)

Payload/Range

Gross weight of the AA-1 ranged from 1,500 to 1,600 pounds, with empty weights running around the l,000-to-1,l00 mark with normal VFR equipment. The typical 450-pound useful load of the AA-1 and AA-1A allows for two 170-pounders, 18 gallons of fuel (a bit less than full tanks) and nothing else. (The -B and -C models will haul about 50 pounds more.) Get a couple of fatsos on board, and you'll be overgross real fast. "It makes a good single-place airplane," comments one owner who lives in Albuquerque, elevation 5,000 feet. The unfortunate irony is that, at the same time the limited useful load encourages pilots to overload it, the AA-1's takeoff and climb performance degrade drastically in an overload situation. This is one airplane in which weight limits should be strictly observed.

Primitive Fuel Gauge

Fuel capacity is just barely adequate. The tanks hold 24 gallons, of which 22 is usable, good for maybe two and a half hours with a slim reserve. Comments one owner, "The practical range is low, about 250 nm. Once I went 300 nm, but the adrenaline content was high, and I had only four gallons when I landed." The range problem is exacerbated by the AA-1's primitive fuel gauge system, which is highly inaccurate and demands extra fuel margins just in case. All in all, it's probably prudent to consider the AA-1 a single-place airplane at even modest density altitudes. By all means, never overload it. And don't try to fly it much more than two hours at a stretch unless you throttle well back.

Handling Qualities

Finally, it's time for some good news. Those suspecting us of Yankee-bashing will be pleased to read that the AA-1 series has marvelous fighter- like handling qualities --or sports-car handling, if you prefer the automotive cliche'. Pitch and roll control are astonishingly quick, and will come as a revelation to Cessna-trained pilots. There's hardly a better airplane for zooming around clouds in mock dogfights, indulging one's fighter pilot fantasies. For all its aerial agility, however, the AA-l is not approved for aerobatics. Loops, rolls and spins are forbidden. We imagine that plenty of Yankee pilots have done rolls and loops without hurting themselves (watch the induced drag at the top of the loop), but we can't emphasize enough that no one should ever spin an AA-1. It tends to go flat (especially the -A and -B models), and in the early days spins were the leading cause of AA-1 fatalities. Unfortunately, the other side of the quick-handling coin is marginal longitudinal stability, which makes airspeed hard to control The AA-1 is by no means an IFR airplane - don't even think of serious instrument flying in this one. At cruise speeds, simply leaning forward and back in the pilot's seat will trigger 500 fpm altitude excursions.

At slow speeds, the Yankee tends to wander away from its trimmed airspeed. In pilot's language, the Yankee is a twitchy little sonofagun.

Poor Stability

The poor stability presents problems on landing. In 1969, military test pilots at Edwards AFB evaluated the AA-l's handling qualities. The final report noted, "Oversensitivity of directional and longitudinal control system presented a problem on both takeoff and landing . . . too light in pitch." An aeronautical engineer/ student pilot who participated in the evaluation noted, "Longitudinal stability is so low that beginning pilots are unable to maintain or control airspeed... the low stability contributes to a tendency to over flare the airplane." On the ground, the AA-1 is highly maneuverable. With its free-castoring nosewheel, the AA-1 must be steered with brakes at low speed, and it can pirouette with astonishing agility. At the beginning of the takeoff roll, aim well to the right; by the time the nose swings around to the left, the rudder will be effective. otherwise, you'll have to ride the right brake during the early part of the takeoff, which degrades the already mediocre takeoff performance even further.

Cockpit/Cabin

The first thing everybody notices is the Yankee's sliding canopy. If you're young and agile and wearing pants no problem, but others may not like it. The canopy provides superb visibility and adds to the fighter plane ambiance. The cabin sound level is deafening, however, particularly in the early models. "The noise has to be heard to be believed," comments one owner, who uses noise attenuating headphones. "Without them, hearing loss is a virtual certainty," he says. The AA-1 is roomier than a Cessna 150 (but then what isn't?), and the clear canopy adds to the feeling of spaciousness. The seats are Spartan. The panel is fairly standard for modern aircraft, much better than the random arrangements of post-war two-seaters.

The AA-1's major ergonomic disaster is the fuel system, particularly the gauges. There is no "both" position on the fuel selector; one must select either the right or left tank. This can lead to inadvertently running one tank dry, and is much less safe than the simple on-off system in the 150 or the left-right-both system in larger Cessnas. The fuel gauges themselves are laughably primitive: a couple of clear plastic tubes beside the occupants' knees on the left and right sidewalls. The tubes are plumbed directly to the fuel tanks, and the pilot gauges the fuel level by watching the fuel in the plastic tube. Admirably simple in theory; the only problem is that it doesn't work worth a damn. "Pathetic" is how Antoniou described it.

Accident Record

Here's what Yankee buffs don't like to talk about: accidents. The AA-1 series has historically had a very bad safety record. Although the AA-1's accident rate has improved significantly over the years (as has all of general aviation's), the latest news is still bad: an exhaustive Aviation Consumer study of all AA-1 accidents from 1976 through 1984 reveals a total accident rate of 14.6 per 100,000 aircraft hours, and a fatal rate of 3.2. Although this is better than it used to be, it's worse than average for two-seat aircraft. The Cessna 150/152, for example, had a total accident rate of 10.0 and a fatal rate of 1.1 - barely a third of the AA-1's. Yankee accidents tended to be more serious as well; 22 percent of AA-1 crashes were fatal, compared to only 11 percent for the 150/152. AA-1 boosters insist that you can't blame the plane if some idiot flies it into a mountain in a thunderstorm. Surprisingly, however, only three out of 48 fatal AA-1 accidents we studied were weather related. By contrast, a random sample of Cessna 172 accidents showed that nearly two thirds of Skyhawk fatalities involved bad weather. Clearly, it's not those big black clouds that are getting AA-1 pilots into trouble. What is?

Leading cause of AA-1 accidents was engine failure, due to both fuel mismanagement and mechanical failures. In 29 percent of AA-1 accidents and 25 percent of the fatalities engine wasn't running when the plane hit the ground. By contrast, the Cessna 172 showed only 11 percent engine failures.

Fuel Mismanagement Nemesis

Fuel mismanagement was the prime culprit. Nearly one in five (18 percent) AA-1 crashes was triggered by fuel starvation or exhaustion. The comparable figure for the Skyhawk was just five percent. The AA-1's primitive fuel system is clearly at fault here. The other 11 percent of AA-1 engine failures were due to mechanical or undetermined reasons, double the Skyhawk ratio. Leading cause of known mechanical failures was broken or stuck valves. This will come as no surprise to AA-1 mechanics; the tightly-cowled 0-235 engine tends to run hot in the AA-1, which puts extra stress on the valves. We noticed another pattern of AA-1 accidents: failure to clear obstacles on takeoff, which accounted for seven percent of AA-1 crashes, but just one percent of C472 accidents.

The AA-1's combination of high wing loading, low aspect ratio and high induced drag at low speeds make it a ground lover, particularly on a hot day, with a heavy load, or on a grass runway.

"Low"-Jinks

Buzzing was a major killer of AA-1 pilots; nearly 20 percent of AA-1 fatalities resulted from low-altitude high-jinks gone awry. Obviously, the pilot deserves most of the blame for buzzing accidents, but the AA-1's sporty aura no doubt encourages pilots to try buzz jobs, and the plane's tendency to lose speed rapidly during maneuvers and to stall abruptly (especially the hot-wing airplane) make buzzing far trickier in the AA-1 than in other aircraft. Several fatal AA-1 stalls also occurred after engine failures, and the overall rate of fatal stall accidents was double that of the Skyhawk. In the early days of the AA-1, spins were the number one killer. Through 1973, the Yankee had a spin fatality rate five times higher than any airplane then in production. (The factory prototype AA-1A, in fact, was lost in a spin test.) The FAA launched a special investigation of the Yankee's spin traits, and concluded that, although it barely met the letter of the certification regs, there was a "safety of operation" problem with the airplane. (The final version of the report, by the way, had the reference to a safety problem expunged after the then-president of American Aviation, Russ Meyer - now Cessna chairman - put pressure on FAA higher-ups.) An AD was issued in 1974 requiring a big red "Spins Prohibited" placard, and the word eventually got out to the pilot community that the Yankee could be a killer in a spin. As a result, spin accidents have declined dramatically in recent years Comments one long-time AA-1 instructor, "In the early 1970s, when my ignorance still prevailed, I did three-turn spins and put pre-solo students through one-turn spins. . . however, a long conversation with Grumman test pilots told me that, prudence was the better part of valor, and I stopped doing them."

Pilot Time In Type

As we pored over AA-1 accident briefs, one factor leaped off the pages: low pilot time in type. Comparing the AA-1 to the Cessna 172, we found that although the median total time of the pilots involved in accidents was comparable - about 200 hours in each case - there was a big difference m median time in make and model: only 28 hours in the Yankee, compared to 65 hours in the Cessna. Looking at it another way, nearly a quarter of all AA-1 accident pilots had 10 or fewer hours in type, while only 12 percent of the Skyhawk pilots were such neophytes in type. We noticed a startling number of pilots with plenty of overall experience who were just transitioning into the AA-1. An astounding 17 percent of all AA-1 accident pilots had more than 100 hours total time but 10 hours or less in the Yankee. Only two percent of Skyhawk accident pilots fit that profile.

A typical example: In June, 1983 in Mechanicsburg, Pa., a 6,000-hour ATP with just three hours of AA-1 time tried to take off on a rough grass runway. He overestimated the airplane's ability to climb, failed to get airborne and crashed off the end of the runway. It appears that the AA-1 really eats up pilots who have little experience in it. Cessna and Piper hours mean very little, and may even lull pilots into a false sense of security. Comments one veteran AA-1 instructor, "I have never dared to check out a pilot in an AA-1 in less than three hours, regardless of their piloting background. Cessna pilots almost always require extensive retraining, usually eight to ten hours."

Moral: if you're transitioning into an AA-1 - no matter how experienced you are in other aircraft - get a thorough checkout by a knowledgeable AA-1 man and be very cautious for the first 50 hours.

American Yankee Assn.

In contrast to the grim accident statistics for the AA-1 overall, the pilot-members of the AmericanYankee Assn. have compiled a startlingly good safety record in the AA-1. AYA members get special reduced insurance rates for their Yankees, about 25 percent below market, with premium reductions in each of the past three years. And they've earned them: for the years 1984-1987, with an average of more than 100 airplanes enrolled in the AYA program, there wasn't a single accident claim. This fine record underlines the importance of pilot time-in-type in the AA-1 safety equation. The AYA insurance program requires at least 10 hours in AA-1s, and most AYA members are Yankee veterans with hundreds of hours in the airplane. AYA has also established what it calls a Pilot Familiarization - Program, in which new members are urged to take a check ride with an AYA type member to learn the airplane's idiosyncrasies. We strongly urge that any potential AA-1 buyer join the AYA and get a checkout from an AYA pilot. (The insurance savings alone will pay for your dues many times over.) American Yankee Assn., P.O.Box 1531, Cameron Park, CA 95682- 530-676-4AYA. And, as long as we're saying nice things about the AA-1 safety-wise, we should mention that the airplane is stoutly built indeed. The bonded honeycomb skin, because it can't be easily tapered, is thicker than it has to be in many places. Likewise, the wing spar is "too" thick outboard. That doesn't help the empty weight, but it does help you in case of an accident. One flight school reported that in four low-altitude stall accidents, its students suffered no injuries. And if you have to ditch your Yankee, it will float better than other aircraft because of the bonded honeycomb fuselage skin.

Cost/Performance/Specifications
 

Maintenance

Readers and mechanics tell us the Yankee is a simple, robust airplane that holds up well if cared for reasonably. Annual inspections typically run about $400-500, with one report as low as $200. (The owner helped out the mechanic by removing inspection panels and so forth.) The most expensive annual reported was $1,500, but the owner explained, "My standards of airworthiness seem to be somewhat higher than those of the previous owner." Every airplane has its maintenance idiosyncrasies, and here are the Yankee's:

Biggest potential maintenance nightmare is delamination of the bonded skins in pre-1976 models. Carefully check bondlines along the control surfaces and assure the presence of "peel rivets", as required by a 1976 AD. To check the wing trailing edge, tap along it with a quarter. AA-lBs built between April, 1974 and December, 1975 - roughly serial numbers 400 through 600 have a special debonding problem; they were built with a defective bonding sealant that caused severe delamination in some aircraft, especially those in warm tropical areas. Check for defective sealant by pulling off the wingtip and inspecting the bonded seam at the spar-to- rib or skin-to-rib joints. If you see purple, you have the bad sealant and the potential for some major problems. If you see a vanilla color, you're okay. Also, according to a former Grumman American employee, some 30 to 40 defective honeycomb fuselage test panels somehow found their way into production aircraft in 1975, possibly affecting AA-1Bs with serial numbers near 500. ( Hot-running engines in pre 1977 models trigger valve and cylinder problems and shorter engine life.

Check carefully for low compression before buying, especially the rear cylinders. Glazed cylinder walls and high oil consumption, often requiring top overhauls in the 800 - 1,000-hour range, are chronic AA-1 problems, particularly in the early models. The problem was ameliorated somewhat by improved baffling in 1974 models, better oil rings in 1975 and larger cowl inlets and cooling louvers in 1976, but the problem wasn't really solved until 1977, when an oil cooler was added. One big AA-1 operator tells us that retrofit of a Grumman American oil cooler kit and the improved rings (actually, just turning the old ones upside down does the trick) help keep the engine cooler. Also, carefully check engine baffling for cracks or leaks. Bad baffles can disrupt cooling airflow and make the engine run hot.

Lead fouling has been a major problem in the AA-1C, which uses the medium compression O-235-L2C. "The older the engines get, the worse the lead-fouling gets," says Ken Blackman. Lead shorts out spark plugs, causes valve sticking, and contaminates the oil with lead sludge, among other things. To cut down on lead problems, lean the engine aggressively (especially on the ground and at low power in the air), avoid high-lead 100-octane (green) fuel, change oil at 25-hour intervals, and use TCP anti-lead additive. An external oil filter, such as the Frantz or O'Berg, will help filter lead sludge out of the oil. Nosewheel shimmy can be a problem if the nosewheel assembly is not meticulously adjusted and maintained. Clean and adjust the nose fork at each annual, and adjust the three washers to the proper torque. Also check the nosewheel strut where it joins the torque tube support. Dozens -if not hundreds - of student pilots may have porpoised their brains out while attempting landings, possibly cracking the mount or loosening the bond. Rock the nose of the airplane up and down; if you hear a clicking sound, the strut is probably loose.

Check for cowling wear. AA-1s tend to get loose and work their way forward, wearing holes in the metal.

Check for brake wear. Because of the steer-by-brakes system, the brakes can wear out quickly. Old AA-1 pros minimize brake wear by starting their takeoff. rolls aimed well to the right and zig-zagging along the taxiways in crosswinds Chrome and stainless steel discs seem to help; one owner reports, "I installed a set of stainless steel brake discs last year, and my brake pad life went from 30 hours. to 200 hours."

Airworthiness Directives call for replacement of the rudder springs every 1,000 hours and the mixture cable every 500 hours. Be sure to check for compliance.

As with every airplane, check for corrosion. The main landing gear attach fitting is a problem area, according to Don Andrew.

Modifications

Yankee owners tend to be the hot-rodder type, and modifications for the airplane abound. Air Mods NW, P.O. Box 8, Snohomish, Wash. 98290, (206) 691-7634, offers the following STCed mods:

125-hp Lycoming engine conversion.

For the AA-1C, the mod is accomplished simply by installing high-compression pistons. In addition to boosting performance, this is claimed to dramatically reduce the -1C's chronic lead-fouling problems. For older AA-1's, an entirely new engine must be installed, and this gets pretty expensive. A "long-nose mod", essentially a cowling from an AA-5, may also be fitted with the 125-hp conversion.

150-hp Lycoming conversion.

A whole series of O-320 conversions will shortly be approved for the AA-1 series Blackman claims his new mod is much cleaner and more efficient than older 150-hp engine mods. For the present. Gross weight may be increased only by 40-60 pounds (except for the -C, which is still limited to 1,600 pounds) so useful load and range will be severely limited, but Blackman is working on a gross weight increase to 1,750.

Auxiliary fuel tanks to increase fuel capacity by 10-20 gallons. Fuel is transferred from the aux tanks into the main tanks, so the selector and gauging system remains unchanged. A gross weight increase of 84 pounds is allowed with the aux tanks

A dorsal fin increases rudder power and reduces tail-wag in turbulence.

Landing gear fairings increase speed by about 10mph, according to Blackman.

Fletcher Aviation (Fletchair) at Houston's Hobby Airport holds STC's for AA-1 engine conversions to most models of the O-320 Lycoming, both 1`50 and 160 hp. Fletchair also sells prop mods, speed fairings and digital fuel monitors supplied by others. Fletchair is the prime source of AA-1 parts in the country and was recommended by numerous AA-1 owners.