Mitsubishi MU-2, Bad Plane or Pilot Error?

By:       Norm Goyer

During the time period that the Jet Commander and the Westwind were introduced another aircraft made its debut. This time it was a very sleek, very fast, very controversial MU-2 twin propjet. This shoulder wing speedster was the most shunned by our refueling crew. The aircraft had tip tanks that were usually burned off first and almost always had to be filled or topped off by our fuel crew. Sounds routine, but not on the MU-2. The tip tanks were at eye level and you needed to release the pressure before opening the locking cap. To release the pressure you had to press the release valve. Then there would be a swoosh of air very often combined with Jet A, under high pressure. The experienced crew men learned to stand aside when releasing the pressure, new fuel personnel made the mistake of standing in front of the fuel cap with predictable results, screams and curses emitted at great volume. Of course we could have warned the fuel crew about the MU-2 “douche tanks” but that would have ruined the fun.

The wings have full-length extending flaps and slats greatly increasing the wing area when deployed. Spoilers are used in place of ailerons for roll control.

Reflexes can often cause pilots trouble, when the almost automatic reactions are contrary to a different type of aircraft and the MU-2 was different. The MU-2 attained its 300 mph cruise by employing a very small wing, this wing, very similar to airliner wings, could greatly increase its area by deploying leading and training edge flaps and slats. This allowed the aircraft to be able to greatly slow down for easy landings. Because the Mu-2 had full span flaps, spoilers were installed in the wings. These were very efficient and enabled the aircraft to be maneuverable without having any ailerons for roll control. So what caused the unusual high number of accidents with this aircraft? Both the manufacturer and the FAA ran exhaustive tests and found that the aircraft was indeed a safe with no bad habits; it became apparent that the bad habits belonged to the pilots, not the Mu-2. If a pilot was forced to make a sudden go-around the pilot in many cases reacted quickly with the wrong control inputs. In almost all other twin-engine aircraft, if you lost an engine or had to make a quick go around the pilot would reduce the angle of flaps to decrease the drag, so the plane could accelerate more rapidly. In an MU-2 if the flaps were pulled back at low speeds the wing would suddenly become much smaller with a resulting loss of lift and a resulting settle into the ground or a stall crash.

The Mitsubishi MU-2 is a very fast, twin-engine, turboprop aircraft.

Working as a team, engineers, experienced Mu-2 pilots and the FAA finally found the reason for so many crashes. All MU-2 pilots were urged to obtain more instruction on the proper way to handle the MU-2 go-around conditions. Log books had to be signed off proving the pilot did indeed qualify as an MU-2 pilot. The crash rate of the MU-2 dropped almost overnight with zero accidents for one whole year. But pilots are prone to blame the aircraft, the weather, anything but admit that they were the reason for the crash. It is now mandatory for all MU-2 PICs to receive annual training.

The aircraft offers great efficiency in operation making it popular with small businesses.

The Mitsubishi MU-2 first flew in 1963 after seven years of intense development. It has become Japan’s most successful aircraft design. Of course the Zero, also a Mitsubishi, of World War II infamy, was also a super successful aircraft.  In 1965, Mitsubishi established a production facility for North American MU-2 buyers in San Angelo, Texas. When MU-2 production ended in 1986, aircraft were no longer assembled in Japan. Instead, the San Angelo Mitsubishi International factory had been building aircraft using American avionics and airframe components shipped from Mitsubishi’s facilities in Japan. Over 750 MU-2 aircraft were sold.

The first MU-2s were powered with Turbomecca engines, the MU-2Bs had Garrett TPE331 turbo prop engines. There were many versions or dash numbers of the MU-2 produced including pressurized and non pressurized military versions. Stretched model MU-2Gs were also available. A variety of engines, mostly, Garrettt, were available with increased horsepower. Some of the last MU-2s produced also used a four-bladed prop. The MU-2 remains as one of most unusual and efficient twin propjets ever produced. Once mastered, pilots loved the way it flew, it was more fighter jet than passenger jet. During World War II the Martin B-26 Marauder encountered a similar pilot problem, See this week’s Bird of the Week for a profile of the infamous “Widow Maker”.

Specifications:

Performance

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Comments

  1. Pat Cannon says:

    Glen;

    You got some of your facts right, but are a little out of date on others. I assume you wish to publish fact and your attempt makes some good points. Please visit the website address shown for the facts. This is the official web site of the MU-2 and deals with some of the myths that have been floundering about for years. In addition, no one uses the old pressure relief method anymore. Pressure is relieved at the cap now for the very reasons you mentioned. The sniffle valve, which was used in the early days to relieve pressure has another more important function to regulate tank over or under pressure in flight. Pressure relief was a secondary function when the old, one step lock, fuel cap was used. Virtually all of those are gone now. Current training dictates relief at the new style Gabb cap.

  2. Kent Titcomb says:

    I am curious about the comparison between the Turbo Commanders and the Mitsubishi. Values, safety, economics etc.

    If a buyer were to consider both, what are the pros and cons of either.