Pilots browsing through the light turboprops as a natural step up from a piston twin might be drawn to the Mitsubishi MU-2s by the lure of dazzling speed, unbeatable short-field work and a less-than-shocking purchase price. However, the airplane has a reputation as being hot and dangerous. Most owners attribute this to bad press, but the press had to come from somewhere: in this case, it was the accident rate, which was very high in the early years-so high that the FAA considered requiring a type rating for the MU-2. That never came to pass, however.
So, is the MU-2 unsafe? Owners universally say no, but…. The but is the need for initial and recurrent training. One respondent said that hes already been to Flight Safety twice this year, and is planning to go again. Thats higher than average, but all of the owners who replied to our request for feedback stressed the need for good training.
The MU-2 can be a real bargain. According to the Aircraft Bluebook, a cabin class piston twin like the 1980 Cessna 421 currently goes for a steep $490,000. This makes a used 72 Mitsubishi MU2F, for example, a rather attractive alternative at around $370,000, not all that much more than an airplane like the Beech Duke, which has a current value of $345,000 for a 1980 model. Try to break into the turbine market with something like a used King Air, even of the same vintage, and the ante goes up dramatically.
Naturally, theres a catch in the step up to turbines; in fact, there are two. One is greatly increased cost per hour; the other is handling and ease of pilot transition.
The MU-2s were among the earliest turboprops to appear on the market, and they are airplanes designed to meet certain specific design criteria. The first of these is speed. For that reason, a small, highly loaded wing was used. The second was short and rough field performance. That meant the use of full-span Fowler flaps, which left no room for ailerons: the MU-2 uses spoilers for roll control. The rough field capability was dealt with by massive landing gear.
History
The MU-2s are the result of a true international amalgam. The airframe was built in Japan by Mitsubishi and shipped to the United States for assembly and addition of AiResearch engines along with avionics and other systems. According to Dick Allan, a broker who does a lot of MU-2 business, some 70 percent of the cost of the airplane came from U.S.-built systems. After an initial marketing relationship with Mooney Aircraft in 1965, Mitsubishi set up a wholly-owned subsidiary for assembly and sales in 69 (when Mooney went bankrupt). Currently, the airplane is officially handled through Beech; however, most operators get all their support from International Jet, a business specializing in the MU-2.
After the debut of the first MU-2B model, Mitsubishi brought out a dozen upgraded models with enhancements ranging from major fuselage enlargements to boosts in engine power and jumps in gross weight.
The MU-2D followed the -2B, offering integral wet-wing tanks instead of bladder tanks, higher weights, higher pressurization and four-position flaps.
The F model received engines of 665 SHP, up from 575, and extra fuel. The G was the first stretched version, with a cabin about five feet longer, made possible by the addition of pods to the sides of the fuselage to accommodate the landing gear (making the airplane slightly reminiscent of military transports like the C-130).
In the J model the interior was redesigned slightly to provide another 11 inches of cabin room. Also, extra soundproofing was added to the later Js.
The L received bigger 715 SHP engines, increased gross weight and pressurization. The M boosted gross, pressurization, and certified altitude. The N and the P offered an engine slowdown and four-bladed props for sound reduction. The Solitaire and Marquise with -10 engines boosted altitudes and speeds. These last two were introduced in 1979, and remained in production until the line was closed down in 1985.
Noise
Perhaps the most significant improvement came with the 77 P and N models, when a major effort was made to combat the aircrafts reputation for annoying cabin noise levels. A big change was made at that time by slowing down the engine RPM, adding a fourth prop blade and enlarging the prop diameters. Owners say this hushes the cabin sound levels dramatically, by 10 dbA or so, though ironically the greatest din is still experienced during taxi, since the AiResearch Garrett TPE 331 engines are spooling up at around 65 percent RPM, unlike the P&W PT-6 engines, which idle in a more subdued, conventional fashion.
In fact, if theres one main complaint aired by MU-2 pilots, especially about the earlier models, its the inescapable noise and vibration of the Mitsubishi aircraft.
One pilot of a 1975 M model said his company had taken sound level readings in the aircraft that showed extremely high decibel levels in front, becoming progressively lower toward the back of the cabin. They recorded levels of from 95 to 102 dbA in the pilot and copilot seats, down to 87 to 90 dbA in the middle seats and 80 to 85 dbA in the rear seats while cruising at an altitude of 22,000 feet. He figured that later models with the engine slowdown dropped an average of 10 dbA across the board inside the cabin.
Cabin room
Despite the seemingly small cabin size when viewed from the outside, owners describe the interior as quite roomy and comfortable. The short models seat six in an executive configuration, the long ones eight, though as many as 11 can be accommodated in for air taxi hauling by eliminating facing seats and tables. The long models even come with private toilets and cabin-size baggage areas. The short ones have three separate baggage bays in back of the cabin, with the front one pressurized.
Two areas which received universal praise from pilots were riding comfort in turbulence and structural integrity. Thanks to the high wing loading on the MU-2s, the aircraft sails through chop with small discomfort. And everyone raved about the ruggedness of the Mitsubishi aircraft (in part the result of design for rough field operations).
Payload
Payload appears quite good, especially on later models with higher-output engines not power limited by temperatures on warm days. The chief pilot of an organization that operates a short 75 MU-2 M model said he could fill the fuel tanks, allow 250 pounds for himself and his Jepps, etc., and still load on board five passengers and 214 pounds of baggage. His payload was 1,376 pounds.
When it comes to out-and-out speed, the Mitsubishis lead the pack and always have. The later models can be expected to yield over 300 knots (short models) and the long models only a whisker under that. Aside from much more expensive airplanes like the Piaggio Avanti and Beech Starship, only the Swearingen IIIB comes close at 300 knots, and the Cessna Conquest at 293 knots. The small Beech King Air C90 trails way back at 222 knots and even the King Air 100 only makes it to 248 knots. The Piper Cheyenne I checks in at about 249 knots and the II at 283 knots. A typical seats-full range on the later MU-2s works out at a bit over 1,000 miles, which is average for this class of aircraft, though its overshadowed by some like the Conquest (1,232 miles) and Swearingen IIIB (1,393 miles).
The earlier model MU-2s (Bs, Ds and Fs from 67 through 71) had cruise speeds that were lower by 35 to 65 knots, and commensurately lower range.
Handling
When it comes to handling, there is common agreement that the MU-2s are more demanding for the step-up pilot than other turboprops like the Beech King Air and the Piper Cheyenne. The feel of the aircraft is different because of the spoilers. And many confess that the other side of the coin relating to the MU-2s outstanding short-field performance is that the airplane can be a tough to land with finesse.
Pilots talk about descent rates on final as high as 2,000 FPM, if called for, with the props back in flight idle and 40 degrees of flaps hanging from nearly the full length of the MU-2 wing. The flare calls for a skilled touch to prevent a hard landing, though if the engine flight idle is properly adjusted this tendency is dramatically reduced. Even when the mains are on, the nose wheel wants to fall even if the pilot tries to hold it off with elevator. One owner complained that he was forever experiencing flight director failures which, correctly or not, he attributed to the pounding it took each time the nose slammed down on landing. It is generally agreed that the short models are the worst in this regard, due to the CG location in relation to the main wheels.
One MU-2 flier offered this parallel: If you can fly a Rockwell Shrike or a Mooney, you can fly and comfortably land a Mitsubishi. It wants to float down the runway, so you want to get it right down there on the flare. You dont want a 30-foot initiation of flare; you want it at three feet. And you want to keep the power on til touchdown.
People transitioning into this aircraft tend to slow it up in the flare and get back to flight idle, trying to hold the nose off. It doesnt work. This airplane has to he flown onto the runway. Once youve got the mains on, the nose gear is going to plant itself. It seems abrupt to the pilot.
But this pilot said the aircraft could take the punishment. That nose gear is tough, he said. I dont know of any damage to the MU-2 nose wheels because of this characteristic.
Safety record
The MU-2 has, in the past, displayed a greater than average accident rate, which is the underlying cause of its reputation. However, of late operators seem to be more cognizant of the need for recurrent training, and the rate has fallen. Its also difficult to draw statistically valid conclusions due to the overall low number of accidents. Nevertheless, the record is instructive and highlights the areas pilots need to be aware of. For example, the number two accident problem with the MU-2 models in a 13-year accident rundown turned out to be hard landings. The number three problem area was undershoots-as might be expected in an aircraft that can be set up for a high sink rate on final, with the possibility of getting behind the power curve.
The leading probable cause for accidents in the MU-2 was engine failure. This was also blamed for the greatest number of fatal accidents in the MU-2-three. This is somewhat deceptive: on all three of these fatals, only one engine failed, but the pilot was unable to make a safe return with the remaining powerplant. A stall/spin was blamed in each case, with the pilots accused of diverting attention from flying the aircraft. All this reinforces the case for recurrent training.
This might suggest that the loss of an engine, especially on takeoff and climbout and in the landing pattern, can he a serious cause for concern in the MU-2. In fact, the only safe return with an engine out was made when the failure occurred during normal cruise and the pilot apparently had the time to sort things out and make it to an airport. The airplane, like other turboprops, is certainly able to fly on one engine; however, the pilot has to stay ahead of matters.
It should be noted that the six engine failure accidents (and one incident) were all evidently the result of some sort of malfunction. Another four engine failures occurred because of fuel exhaustion, caused, in turn, by pilot mismanagement; and three other fuel exhaustion accidents were the result of mechanical failures.
Though there are three main sets of fuel tanks in the MU-2, the monitoring system would not appear to be inordinately demanding. There is one main tank in the central wing section into which outer wing tanks feed by electrical fuel pump and into which the tip tanks feed by pressurization from engine bleed air.
Since both engines feed from the center tanks, there is not even a need for crossfeed arrangement, and all the pilot has to do is monitor the transfer of fuel from the outer tanks into the center ones. We noted no accidents from landing with asymmetrical tip loadings.
The last significant cause of MU-2 accidents disclosed in the NTSB briefs is gear-up landings. In the years surveyed there were seven of these altogether-and in four of these the pilot simply forgot to lower the gear.
Service difficulties
For the most part, complaints center on isolated systems, and there appears to be no real pattern. Owners love the ruggedness of the airplane. One respondent, who used to fly a Cessna 340, has found that he can budget less for maintenance reserve with the MU-2 because it doesnt break down as often. Another flight department has a 99% dispatch rate.
In our last look at the MU-2, we had a few very negative comments, including one owner who finally gave up and bought a King Air. Not so this time around. We were fortunate for this article to be able to tap into a large gathering of MU-2 operators at the 1995 NBAA convention in Las Vegas. A survey form was handed out, and the results indicated overall satisfaction with service and parts availability. As noted above, most operators use International Jet for support, and have expressed satisfaction with their service.
Naturally, operators of large piston twins must brace for the quantum cost jump when they make the move to turboprops, but there are those who maintain that the fantastic speed of the MU-2 series will actually deliver a better cost per seat mile than the piston machines.
The AD history of the MU-2 has been fairly quiet of late, though there have been a few notable directives: 95-1-2 called for replacement of the prop blades and hub, while 94-4-16 and 93-7-11 called for alterations to the pitch trim mechanism to limit its nose-down deflection.
Mods
The most significant mod is an engine upgrade available for the MU-2F and -2G, from National Flight, carrying the rather unfortunate name of Super Dave.
Owner Comments
I purchased a 1981 Mitsubishi Solitaire in December of 1994. Previously I owned a Cessna 340, Seneca III, and a Twin Comanche. It is difficult to compare four such diverse twins, but easy for me to analyze reliability.
This airplane is the most reliable I have ever operated. I have now flown it 183 hours and other than 50-hour phase inspections the only maintenance costs I have had were a failed gear down-limit switch ($285) and a failed fuel transfer pump ($1200). The phase inspections cost me about $600 each; so far there have been no parts needed during these inspections. I also had my fuel injectors cleaned for $1200. Other than fuel and engine reserve that has been it.
Every other airplane I have ever owned cost me more for the same amount of flight time. My hourly costs including reserves, hangar and insurance are $320.40, versus $212.70 for the 340. For a typical trip (New Hampshire to Florida), the 340 took 5 hours, 45 minutes. The MU-2 takes only four hours. Interestingly, the cost for both airplanes works out to about $1280, but I now have better performance and reliability. Removing insurance and hangar costs its still a wash: the MU-2 does the trip for $1000, the 340 for $1009.
I attribute the poor accident rate to untrained pilots. This is not an airplane that a low-time or untrained pilot should fly. I do believe in Flight Safety training; Ive been twice this year, and will go again before the year is out. I fly the airplane at least once a week to stay current. I do not believe this airplane should be flown infrequently.
This airplane is the best bargain in the used turbine fleet. I cant imagine why anyone would want, for example, a used King Air instead: just look at the speed and operating costs. I would even recommend an old N, M, or P model over a used piston twin. The MU-2 is simply faster and less costly to operate.
-Paul M. Connolly
Nashua, N.H.
I own and operate an MU-2B-40 Solitaire, s/n 423. It is an extraordinary airplane that makes my air travel both for business and pleasure an absolute joy rather than a chore. I operate the aircraft over 400 hours per year mostly around the U.S., but have made two round trips to Europe this summer.
I purchased my MU-2 in the fall of 1993. It had been well maintained, and had zero-time engines. I paid $650,000 for it. By way of comparison I could have bought an Aerospatiale TBM, a 285-knot airplane, for $1.6 million or a new Beech King Air CB90, a 240-knot airplane, also for $1.6 million. Since the MU-2 is a 315-knot airplane at one-third the cost of the alternatives, I naturally chose the MU-2. Since the MU-2 had zero time engines and was beautifully maintained, I regarded it as a virtually new airplane and felt that I could make an apples to apples comparison to the TBM and King Air. The fact that the MU-2 had 4,000 hours on the airframe was, to me, an irrelevancy-the extraordinarily rugged airframe and unique design convinced me that there were a lot more cycles left on a 4,000 hour MU-2 than there are on a new TBM or King Air. I can unequivocally say that it was one of the best investment decisions I have ever made.
Naturally I was concerned about the alleged difficulties of checking out in the MU-2 and, of course, had been exposed to the usual litany of horror stories generally spread by the uninformed. I spoke with many professional pilots who fly or have flown an MU-2. Each and every one swore by the airplane. They told me to get training from Flight Safety and Reece Howell and I would not have any problems. They were absolutely correct. As a low-time multi-engine pilot, I had no problems in checking out on the MU-2. The training was a wonderful experience, and I have total confidence in my ability to handle the airplane. The FAA has conclusively proved that a type rating is not needed for the MU-2, and I will go so far as to say that if a pilot cannot check out in an MU-2, he should not be flying any multi-engine aircraft.
The MU-2 is an extremely fast, efficient, versatile and cost-effective aircraft. Let me comment on each point:
Speed – The 315 knot cruise at flight level 190 is at the lower end of jet speeds and exceeds any other turboprop. [Ed. note: Thats not quite accurate. The Piaggio Avanti and Beech Starship are both faster (the Avanti much faster), but are in another league price- and size-wise.] My view is that jet speeds are wonderful in theory but not always attainable in reality. With ATC delays, the average speed of a 727 in commercial service is 350 knots. While they can go faster, speed restrictions are a fact of life. In fact, I regularly beat jets from Teterboro to my summer home in Nantucket. The MU-2 is generally faster than a jet for stage lengths of 300 miles.
The speed of the MU-2 makes it an aircraft that can fly anywhere in the U.S. without subjecting the passengers to long hours of fatigue. Flying southwest in the winter, one usually has a 50 knot headwind. In an MU-2 this means a ground speed of 265 knots, still very respectable for a turboprop. The King Air CB90 is down to less than 200 knots-piston aircraft performance. I have a ranch near San Antonio, Texas, and regularly fly nonstop to New York at flight level 290 to 310. With a 50 knot tailwind I can average 350 knots with a fuel burn of 200 PPH per engine. This is simply unobtainable in a jet…which brings me to my next point.
Efficiency – The Solitaire can operate at flight levels up to 330. This substantially reduces fuel burn and makes it an extremely efficient aircraft. The Aero Commander 1000 and Cessna Conquest can operate at slightly higher altitudes, but they are often double the price of the MU-2. Trips from California to New York with the MU-2 require only one stop. I believe that this is excellent performance comparable to most light jets with meaningfully less fuel burn. An important factor in efficiency is the very compact size of the aircraft resulting from its unique design. This makes ground handling and hangar storage very easy. Place the MU-2 next to an Aero Commander 1000…the latter is 40% larger and more expensive to store. This is a very important cost benefit over the life of the airplane.
Versatility – The design goals for the MU-2 were speed and short field capability. The MU-2 meets these criteria better than any other turboprop. Not only is it faster, it is also slower. In light configuration with 40 flaps the aircraft can be safely touched down between 60 and 70 knots. With its massive gear, brakes and prop reverse, it can be stopped in a very short distance. I do not believe that any other turboprop has the short field capability of the MU-2. This is a great advantage for me because I am always landing on south Texas ranches with unimproved fields. The MU-2 is specifically designed for this…other turboprops are not.
Cost effectiveness – As mentioned, the initial capital outlay is below the competition. So is the operating cost. A 100-hour inspection on an MU-2 should be between $3000 and $4000. Since many of the aircraft are in commercial service, there are shops around the country that can do the work quickly and efficiently. A well-maintained MU-2 should have very few problems coming into a 100-hour inspection. The airplane is famous for its reliability and low operating cost. The only area that can be a problem is getting insurance for low-time pilots. With proper training it can be obtained but will probably run 50 percent more than for a comparable turboprop. This is an unfortunate fallout from the undeserved bad press the aircraft has endured. However, with an increase in flight time (1000 hours plus) the pilot should get rates comparable to other turboprops.
In summary, the airplane is easy to fly once one learns to trim it and understands its sensitivity to power changes. We who own and fly the MU-2 sincerely believe that it is probably the most unique and reliable aircraft in the world. It is more than just a magic carpet…it is nothing less than a work of art.
-George Baker
New York, N.Y.
Ive owned a 1973 K model for the past year, having flown it 150 hours during that time. I hold an ATP rating with 4000-plus hours. Safety issues surrounding the aircraft prompted my attending both Reece Howells introductory MU-2 course as well as Flight Safetys recurrent training. In addition I flew approximately 25 hours of dual with Reece and a local MU-2 line pilot. I am fairly comfortable in the machine now.
I do not feel that the aircraft is inherently dangerous, but there are six idiosyncrasies which I feel the pilot must be aware of to safely fly the MU-2. 1) Control inputs are much heavier than those of a piston twin, and the pilot must retrim the MU-2 whenever changing pitch or power. 2) In the MU-2 greater attention must be paid to keeping the ball centered, first by setting equal torque from each engine and then using rudder trim as required. 3) using the autopilot during periods of high workload keeps the wings level and solves the tendency of a wing to drop when the pilot is otherwise preoccupied. 4) The MU-2 has better roll control than most other aircraft, but the yoke must be deflected about 30 degrees farther to get the same rate of spoiler-induced roll as with a conventional aileron equipped aircraft. Initially the pilot will be timid in this regard and the aircraft will feel sluggish in its response. 5) the heavy wing loading of the MU-2 requires a stabilized approach, paying close attention to both airspeed and rate of descent on final approach. The pilot must learn to avoid reducing power as the flare is commenced for landing: doing so in an aircraft with high wing loading can result in a very hard landing. 6) Aircraft control on the roll out is best accomplished by equal and gentle application of ground idle or reverse thrust if needed.
Is the MU-2 dangerous? Absolutely not! Is an untrained MU-2 pilot dangerous? He certainly could be! The key to flying the MU-2 safely is adequate training. In exchange for taking the time to learn to fly the machine correctly the MU-2 pilot and his passengers are rewarded with spectacular performance and great comfort at bargain-basement prices. I couldnt be more happy with mine.
-Ken Wolf
Lewiston, Maine
