Mitsubishi MU 2

Design and development

Work on the MU-2, Mitsubishi's first postwar aircraft design, began in 1956. Designed as a light twin turboprop transport suitable for a variety of civil and military roles, the MU-2 first flew on 14 September 1963. This first MU-2, and the three MU-2As built, were powered by the Turbomeca Astazou turboprop.

Civil MU-2s powered by Garrett engines were certified as variants of the MU-2B, using the MU-2B type followed by a number. For marketing purposes, each variant was given a suffix letter; the MU-2B-10, for example, was sold as the MU-2D, while the MU-2B-36A was marketed as the MU-2N.

Production

In 1963 Mitsubishi granted Mooney Aircraft rights in North America to assemble, sell and support the MU-2. In 1965, Mooney established a facility to assemble MU-2s at its new factory in San Angelo, Texas. Major components were shipped from Japan, and the San Angelo factory installed engines, avionics and interiors then painted, flight tested and delivered the completed aircraft to customers. By 1969 Mooney was in financial difficulty, and the San Angelo facility was taken over by Mitsubishi. Production in the United States ended in 1986. The last Japanese-built aircraft was completed in January 1987.

The subsequent production aircraft, designated MU-2B, were delivered with the Garrett TPE331 engines that remained standard on all later models. Thirty-four MU-2Bs were built, followed by 18 examples of the similar MU-2D. The Japanese armed forces purchased four unpressurized MU-2Cs and 16 search and rescue variants designated MU-2E. Featuring slightly more powerful upgraded TPE331 engines, 95 examples of the MU-2F were sold.

The fuselage was stretched beginning with the MU-2G. The MU-2M (only 28 built) is regarded as the toughest and most desired of all short body MU-2s, especially with a −10 engine conversion. It had a short fuselage and the same engines as the MU-2K and stretched MU-2J and had an increase in cabin pressurization to 6.0 psi; it was followed by the MU-2P, which had newer four-blade propellers. The final short-fuselage MU-2s produced were known as the Solitaire and were fitted with 496 kW (665 shp) Garret TPE331-10-501M engines.

The first significant change to the airframe came with the stretched MU-2G, first flying 10 January 1969, which featured a 1.91 m (6 ft 3 in) longer fuselage than earlier models; 46 were built before being succeeded by the more powerful MU-2J (108 constructed). The MU-2L (29 built) was a higher-gross-weight variant, followed by the MU-2N (39 built) with uprated engines and four-blade propellers. The final stretched-fuselage MU-2 was named the Marquise, and like the Solitaire used 533 kW (715 shp) TPE331 engines.

As of 2005, 397 MU-2 aircraft are registered in the United States.

Japan

The Japanese Self-Defense Forces are the only military operators to have flown the MU-2 in front-line service.

Ground Self-Defense Force

The four C-model aircraft built, in addition to 16 MU-2Ks, entered service with the Japan Ground Self-Defense Force (JGSDF) with the designation LR-1; they were used as liaison and photo reconnaissance aircraft. They were retired in 2016. A number of them have been placed as gate guardians at JGSDF bases.

Air Self-Defense Force

29 MU-2Es were purchased by the Japan Air Self-Defense Force as search-and-rescue aircraft and designated MU-2S. Additional equipment consisted of a "thimble" nose radome, increased fuel capacity, bulged observation windows, and a sliding door for dropping rafts. They were replaced in 2008 by the U-125A. Some have been preserved.

New Zealand

In late 2009 the Royal New Zealand Air Force (RNZAF) took delivery of four Mitsubishi MU-2F fixed-wing training aircraft from the United States for use as training aids. In New Zealand service they are known as the Mitsubishi MU-2 Sumo. The aircraft were ferried to New Zealand and are located at the RNZAF's Ground Training Wing (GTW) at RNZAF Base Woodbourne near Blenheim in New Zealand's South Island.

United States

Since 1987 MU-2s have been flown by retired US Air Force pilots working for Air 1st Aviation Companies, Inc under government contract at Tyndall Air Force Base, Florida, where they provide U.S. Air Force undergraduate Air Battle Manager students of the U.S. Air Force Weapons Controller School with their initial experience controlling live aircraft. In the tactical simulations the aircraft usually represent F-15s and Mikoyan MiG-29s. Students must control eight MU-2 missions before they can progress to controlling high-performance aircraft such as F-15s or F-22s.

Flight around the world

On 25 August 2013 Mike Laver, owner and pilot of N50ET (a −10 engine converted 1974 K-model equipped with 5-blade MT-composite propellers, which had just received an STC under Air 1st of Aiken, SC), along with AOPA Pilot technical editor Mike Collins, embarked on an around-the-world journey in the MU-2B-25. The voyage commenced at Aiken Municipal Airport and sojourned in Nagoya, Japan on 14 September 2013; the 50th anniversary of the MU-2.

Safety concerns

Concerns have been raised about safety in operating the aircraft; there have been 337 fatalities from MU-2 crashes. As of October 2005, the United States Federal Aviation Administration (FAA) undertook a safety evaluation of the aircraft. It concluded that the aircraft has met its certification requirements: it is safe when operated by properly trained pilots who operate properly maintained aircraft. The FAA is in the process of mandating training specific to the MU-2, as it has in the past for other aircraft. When such mandated training was required outside of the U.S., the MU-2 accident record was vastly improved.

Because the MU-2 offers very high performance at a relatively low cost, some of its operators lack sufficient training and experience for such an advanced aircraft. The MU-2 has performance similar to a small jet, yet early pilot licensing required only a simple endorsement from licenses for much slower twin piston-engined aircraft. The fact that numerous MU-2 pilots were inexperienced at high speeds and high altitudes seems to have resulted in the high crash rate. Once a type certification was required for an MU-2 license, the accident rate dropped to normal levels.

A design feature of the MU-2 is its high cruise speed, while having a low landing speed. This is accomplished by using full-span, double-slotted flaps on the trailing edge of the wing. These flaps give the MU-2 a wing area comparable to a Beech King Air in landing configuration, while having a wing area comparable to a light jet while in cruise mode. The full-span flaps meant that over-wing spoilers were employed instead of conventional ailerons.

These spoilers are highly effective, even when the MU-2 wing is stalled. Some fatal accidents have occurred because normal engine-out procedures for light twin aircraft are not effective when flying the MU-2. The commonly taught procedure of reducing flap following an engine failure on take off leads to a critical reduction in lift in the MU-2 due to the highly effective double-slotted flaps. When pilots were taught to retain take-off flap and to reduce climb rate in the event of an engine failure, MU-2 accident rates were reduced to almost nil.

From an FAA press release:

The FAA began an aggressive safety evaluation in July 2005. The evaluation is performing a detailed review of accidents, incidents, airworthiness directives, service difficulty reports, safety recommendations and safety reports. It also is examining pilot training requirements, the history of the aircraft's commercial operators and possible engine problems. The goal is to identify the root causes of MU-2 accidents and incidents and determine what, if any, additional safety actions are needed.

In early 2008, the FAA issued a Special Federal Air Regulation (SFAR) directed at MU-2B operations. Pilots flying this aircraft after that date (current MU-2 pilots would have a year to come into compliance) were required to receive type-specific initial training, as well as recurrent training. The agency also required that a fully functional autopilot be available for single-pilot operations, and that FAA-approved checklists and operating manuals be on board at all times. Unusually for this SFAR, pilot experience in other aircraft types cannot be used to comply with MU-2 operational requirements. For instance, the requirement to perform landings within the preceding 90 calendar days before carrying passengers is altered by this SFAR to require those landings be made in the MU-2.

As of 29 March 2016, there have been three fatal accidents involving the MU-2 since the FAA SFAR (Title 14; Part 91, SFAR Number 108) was implemented beginning in 2008.

Short fuselage

XMU-2

Astazou-powered prototype, one built

MU-2A

Astazou-powered development aircraft, three built.

MU-2B

Production variant with Garrett TPE-331 engines, 34 built.

MU-2C (MU-2B-10)

Unpressurised variant for the Japanese Ground Self Defense Force, four built.

MU-2D (MU-2B-10)

Improved MU-2B, higher operating altitude and bladder fuel tanks rather than wet-wings, 18 built.

MU-2DP (MU-2B-15)

MU-2D with 90-gallon tip tanks and upgraded engines, three built.

MU-2E

Unpressuised variant for the Japanese military designated MU-2S

MU-2F (MU-2B-10)

Variant with improved engines and 90-gallon tip tanks as MU-2DP but certified at a higher gross weight and additional fuel tanks, 95 built.

MU-2K (MU-2B-25)

Short fuselage variant of the MU-2J, 83 built.

MU-2M (MU-2B-26)

Revised variant of the MU-2K with increased weight, and increased cabin pressure, 27 built.

MU-2P (MU-2B-26A)

Improved variant with four-bladed propellers and improvements as MU-2N, 31 built.

Solitaire (MU-2B-40)

Variant with improved engines and increased fuel capacity, 57 built between 1979 and 1985.

Long fuselage

MU-2G (MU-2B-30)

Stretched variant with a 1.91m increase in length, larger cabin and change to landing gear configuration, first flown in January 1969, 46 built.

MU-2J (MU-2B-35)

Variant with improved engines, eleven inch increase in cabin length and increased gross weight, 108 built.

MU-2L (MU-2B-36)

Revised variant of the MU-2L with increased weight, and increased cabin pressure.

MU-2N (MU-2B-36A)

Improved variant with four-bladed propellers and other improvements including an extra cabin window, 36 built.

Marquise (MU-2B-60)

Variant with improved engines, 139 built.

Cavenaugh Cargoliner

Freighter conversions of long fuselage MU-2 variants by Cavenaugh Aviation Inc. of Conroe, Texas, by addition of a crew door in place of a flight deck window and a large cargo door in the rear port fuselage. Eleven aircraft had been converted by March 1987.

Military

LR-1

Japanese military designation for MU-2C and MU-2Ks operated by the JGSDF, 20 delivered.

MU-2S

Japanese military designation for a MU-2E search and rescue variant for the air force, 29 delivered.

Aircraft on display

Australia

An MU-2 is on display at the Australian Aviation Heritage Centre at Darwin Airport, Australia.

Japan

MU-2A JA8620 the first production aircraft is on display at the Niigata Science Museum, Niigata.

MU-2B-25 JA8628 the fifth production aircraft is on display at the Museum of Aeronautical Science, Chiba prefecture, Japan.

Mitsubishi LR-1 2209/E is on display at Misawa Aviation & Science Museum, Aomori, Japan.

United States

MU-2 Marquise 1575 is the last assembled MU-2 from the San Angelo, TX production facility. It is currently on display at the Spirit of Flight Center air museum in Erie, Colorado.

Incidents and accidents

1980s

On 24 March 1983, an MU-2B-60, registration N72B, was en route from Jacksonville, FL, to Atlanta, GA, level at 18,000 feet. The aircraft was hauling cancelled checks and had just been handed off from JAX Center to ATL center when it disappeared from radar at approximately 2:30am. The wreckage was spread over a two-mile area. According to the NTSB report, the right wing failed upward and the left wing failed downward.

A spate of accidents involving MU-2s occurred in Australia between 1983 and 1994, some of which were caused by icing on the airframe. This caused the airspeed to decrease to the point where the aircraft stalled and entered a spin.

On 24 May 1983, VH-MLU, an MU-2B-60, crashed near Bargo, New South Wales. The pilot, the sole occupant, was killed.

On 16 December 1988, an MU-2B-60 crashed near Leonora, Western Australia. The pilot and nine passengers were killed.

1990s

On 26 January 1990, an MU-2B-60 crashed near Meekatharra, Western Australia. The pilot and one passenger were killed. The Leonora investigation was extended to include this crash given the same aircraft type crashed in similar circumstances.

On 19 April 1993, an MU-2 reported engine trouble while flying near Dubuque, Iowa. It crashed into a farm silo about nine miles south of that city. All eight people aboard the aircraft were killed, including South Dakota Governor George S. Mickelson. The government-owned aircraft was returning to South Dakota from the governor's lobbying effort in Ohio.

2000s

On 20 December 2005, an MU-2B-36 crashed near Terrace, British Columbia. The pilot and first officer were killed. The Transportation Safety Board of Canada investigation concluded that the left engine combustion chamber plenum split open during take-off due to a fatigue crack, causing the engine to flame out. The crew were unable to safely land the disabled aircraft.

2010s

On 18 January 2010, an MU-2-2B-60 crashed in Ohio on approach to Lorain County Regional Airport, killing the two pilots and both passengers. The passengers were 89-year-old Don Brown, inventor of a grid system for mounting dropped ceilings, and his wife.

On 10 November 2013, an MU-2-2B-25 crashed in woods near Owasso, Oklahoma. Dr. Perry Inhofe, the solo occupant, was killed. He was a son of Senator Jim Inhofe, a Senior Republican Senator from Oklahoma. The NTSB factual report states that Inhofe had no previous experience flying turbine-powered aircraft, and that this was his first solo flight after completing 11.5 hours of training. A subsequent lawsuit filed by his family alleged that one of the aircraft's engines failed just as Dr. Inhofe was attempting to make his first-ever solo landing in an MU-2.

On 29 March 2016, an MU-2-2B-60 operated by Aero Teknic, a Canadian aircraft maintenance company, crashed on approach to Îles-de-la-Madeleine Airport, killing former Canadian politician Jean Lapierre, his family, and the two pilots. Together with his wife, sister, and two of his brothers, he was flying to their father's funeral. The two pilots died, including Pascal Gosselin. While one man survived the crash, he died of a heart attack after being pulled from the wreckage. The flight departed Montreal Saint-Hubert Longueuil Airport around 0930 Eastern time. Approximately 70 minutes later (1140 Atlantic time), the aircraft collided with terrain about 2 km from Îles-de-la-Madeleine Airport, the flight's intended destination.The Transportation Safety Board of Canada (TSB) opened Aviation Investigation A16A0032 for this crash, sending a group of investigators to the site.

On 30 April 2016, MU-2D (MU-2B-10) landed safely without a nosewheel in Airport Eelde, Netherlands. It came from Airport Emden, Germany. All three people on board survived.

Specifications (MU-2L)

Data from Jane's All The World's Aircraft 1976–77

General characteristics

Crew: 1 or 2 pilots

Capacity: 4–12 passengers

Length: 12.01 m (39 ft 5 in)

Wingspan: 11.94 m (39 ft 2 in)

Height: 4.17 m (13 ft 8 in)

Wing area: 16.55 m² (178 ft²)

Empty weight: 3,433 kg (7,570 lb)

Max. takeoff weight: 5,250 kg (11,575 lb)

Powerplant: 2 × Garrett TPE331-6-251M turboprops, 579 kW (776 shp) each

Performance

Maximum speed: 547 km/h (295 knots, 340 mph) at 4,575 m (15,000 ft) (max cruise)

Cruise speed: 483 km/h (261 knots, 300 mph) at 7,620 m (28,000 ft) (econ cruise)

Stall speed: 142 km/h (76.5 knots, 88 mph)

Range: 2,334 km (1,259 nmi, 1,450 mi)

Service ceiling: 9,020 m (29,600 ft)

Rate of climb: 13.4 m/s (2,630 ft/min)

Wing loading: 317 kg/m² (65.0 lb/ft²)

Power/mass: 0.22 kW/kg (0.13 hp/lb)