Mitsubishi garnered top bragging rights in the most recent AIN product-support survey, and the biennial pilots’ review of proficiency (PROP) seminar series is one good reason why. How many manufacturers sponsor regular owner/operator safety seminars–let alone doing so for aircraft that went out of production almost two decades ago? Mitsubishi Heavy Industries America (MHIA) does, and its series has succeeded in significantly reducing the accident rate among MU-2 operators. Now in its 10th-anniversary year, the PROP series has evolved to include topics of primary interest to pilots and operators of the speedy Japanese airplane that many believe is misunderstood.
First sold in 1968, the MU-2 burst on the aviation market as a modern wonder of aerodynamics and propulsion. It was unique in just about every way, from the fuselage-mounted main landing gear (for operation from unimproved strips) to its high-efficiency wing with spoiler roll control, the TPE331-powered twin was a breath of fresh aerodynamic air.
But the MU-2 developed a dark reputation among pilots. A spate of accidents in the mid-1980s led to a resumption of the pilot seminars in 1994 (one series was held in 1982, not to be repeated). Since the seminars resumed, the accident rate for the MU-2 has held steadily within the middle of the pack for its class, according to MHIA statistics. The giant Japanese corporation’s aviation division that is dedicated to MU-2 support calculates there are currently 316 of the turboprop twins registered
in the U.S., with a total fleet time of almost 5.4 million hours. The high-time aircraft–an L-Model, S/N 672–has logged some 23,000 hours, while the baby of the fleet has roughly one-tenth that amount of time on its airframe. The average flight time among MU-2s still flying is 6,183 hours, with 46 airplanes boasting more than 15,000 hours under their belts.
Many operators find the MU-2 a utilitarian workhorse, especially those aircraft originally equipped with the Honeywell TPE331-10s, or those with earlier engines upgraded to Dash 10 specs. The conversion to the later mark of the ubiquitous turboprop affords much improved takeoff, climb and cruise performance–up to as fast as 310 ktas from 270 ktas for the short-body MU-2s. Also, converting to the Dash 10 version of the TPE331 lowers hourly operating costs by as much as $74 through a combination of lower fuel burn and extended maintenance intervals for hot-section inspection and overhaul. Intercontinental Jet of Tulsa, Okla., is one MHIA-authorized MU-2 service center that performs the Dash 10 conversion.
The story of product support for the MU-2 dates back to when Raytheon assumed responsibility for the airplane as part of its deal with Mitsubishi to acquire rights to produce the Diamond light business jet (now the Beechjet 400A/Hawker 400XP). In 1998, Raytheon readily ceded responsibility for the out-of-production turboprop series to Mitsubishi. The Japanese company’s active role in supporting the airplane and its pilots and operators has been a source of some amazement throughout the industry. The cost of keeping the airplanes flying as safely as possible is, presumably, a small price to pay for MHIA to show it is doing everything it can to reduce accidents, thus lowering its vulnerability to liability lawsuits.
MU-2 technical support from MHIA includes field service, engineering services, type-certification maintenance and FAA/NTSB coordination and air safety investigation. The field-service branch of the support structure includes 24/7 customer support, service-center support, reliability review of parts and components, service information review, vendor coordination and spare-parts assistance.
In its customer-support role, TAS handles publication distribution for MHIA for Airworthiness Directives, Service Bulletins and “service news” notifications, less severe but nevertheless important service tips. TAS is also the liaison for training programs; service-center program administration; vendor program administration; spare-parts sales and distribution; customer contact; and the PROP seminars and other safety programs conducted in connection with NBAA and other organizations.
The Richmond PROP seminar began with the latest version of TAS’s MU-2 icing video. As part of an airworthiness directive, any MU-2 pilot needs to have seen the video to exercise the airplane’s authorization to fly in “known icing” conditions. PROP attendees who sat through the icing video filled out certification forms that were then forwarded to the FAA to certify that they had, indeed, seen the program.
On-screen images come primarily from a series of in-flight icing tests performed a few years ago using a U.S. Air Force tanker converted to spray a cone of dyed water behind it. The same tanker was used in icing-evaluation tests for the ATR regional airline turboprop series after the infamous fatal icing accident in Roselawn, Ind.
Cameras mounted on the tanker, a chase plane and inside and outside on the MU-2 itself show where ice collects and the effectiveness of the airplane’s anti-icing and de-icing equipment. The severe icing that is most dangerous originates with so-called supercooled large droplets (SLD) of water. The droplets can be hundreds of times larger than droplets that cause less severe forms of ice, such as rime. With SLD, the moisture splatters on the cold-soaked surface of the airplane and freezes on contact, often spreading aft beyond the reach of wing-leading-edge de-icing boots–especially on the underside of the wing. SLD can also cause ice accretion in the engine intake area.
The added weight of the ice is not considered a serious problem for MU-2s. But the degradation of lift (due to changes in the airfoil shape) and the possibility of engine flameout from melting nacelle ice are greater concerns. At the PROP seminars, pilots are repeatedly warned of the danger signs indicating that severe icing could be at hand.
They include loss of airspeed of 20 knots or more; a decrease in rate of climb to 300 fpm or less; unusually extensive visible ice on the undersides of the wings, nacelles, prop spinners or windshield. Cannon explained that the autopilot roll command induces a 25-degree bank, steep enough to invoke a stall if ice has deformed the wing shape and reduced efficiency. If roll is introduced, he said, lower the nose to increase speed to a safer value. Flaps should be avoided, since the increased angle of attack could cause more ice to adhere to the wing’s underside. Also, a preflight inspection must ensure that icing lights are operable if a night flight could enter potential icing conditions. Fortunately, the MU-2 has good stall behavior, according to Cannon, even with an ice-contaminated wing. That was confirmed by the tests performed with simulated ice shapes attached to the wing, he said.
With all the emphasis on icing concerns, Cannon was compelled to emphasize that severe icing caused by SLD constitutes less than 1 percent of icing encounters. Further, said Cannon, the MU-2 has shown itself to be among the best-behaved aircraft of its class in icing conditions. If anything, the extensive testing following the Roselawn accident has clearly identified the best strategies for avoiding severe icing in the first place, and escaping the icing should it be encountered unexpectedly.
Following the icing video presentation, the programs that followed included detailed presentations on pilot tips for engine operation by Honeywell Engines’ Helmuth Eggeling; aspects of flight performance by TAS’s Rick Wheldon; more operational tips from high-time MU-2 pilot Dave Milligan; a service information update from TAS’s Jim Stermer; and an analysis of accidents by TAS’s Cannon. The last item concentrated on identifying the “error chain,” breaking it down into key components and attempting to attach which components led to a particular accident. On the second day of the seminar, Cannon went into far greater detail on individual accidents and their probable cause. This year’s PROP seminars included discussions of accidents at Napa Valley, Calif., and Pittsfield, Mass. Though these accidents have yet to receive an official verdict on probable cause from the NTSB, the PROP seminar opened the discussion among pilots as to what they thought were the chief contributing factors.
Day two of the seminar included a continuation of many of the topics begun on day one, with the addition of a discussion on the service center’s role in MU-2 operations, a SimCom update and a second session of questions and answers, moderated by TAS’s Rick Wheldon. Honeywell’s Eggeling also supplied the answer to the burning question, “Ninety-six-percent or 100-percent power for takeoff?” (For the answer, you’ll have to attend a PROP seminar yourself.)
While attending a PROP seminar could not be considered on a par with conventional introductory and recurrent pilot training, the sessions are really designed to provide operators and service providers with a forum to discuss topics of common concern. The seminar brings together technicians, vendors and aircraft owners for a true face-to-face interaction. The results are a safer, more informed pilot population, a better understanding of its customers for MHIA and an overall improvement in operations for MU-2s.
The two-day PROP seminars are conducted under MHIA contract by Turbine Aircraft Services (TAS) of Dallas. Former MU-2 factory demonstration pilot Pat Cannon plans and conducts the seminars and acts as the master of ceremonies. Conducted around the country at hotels, the seminars feature executive-level amenities, all paid for by MHIA.
In addition, product vendors have a room available to display their wares for MU-2 operators attending the sessions. Vendors include many of the authorized MU-2 service centers, interior shops, Honeywell (for engines and avionics) and other aftermarket producers of components and accessories aimed at MU-2 owners and operators. But the meat of the program is a series of presentations by representatives from MHIA, TAS, Honeywell Engines, Hartzell, SimCom (which conducts MU-2 simulator training) and others.
This year’s series of seminars includes sessions in Dallas (April 2 to 3; 100 attendees); Richmond, Va. (April 16 to 17; 104 attendees); Orlando, Fla. (April 30 to May 1; 86 pre-registrations at press time); and Scottsdale, Ariz. (May 14 to 15; 76 pre-registrations). Scheduled in conjunction with the Richmond and Scottsdale seminars, MHIA and Honeywell Engines sponsor a pilot-familiarization course on the TPE331 engines that power the MU-2. The fee for the course is $185 for PROP 2004 registrants, reduced from the normal cost of more than $1,000. Also, the seminars in Dallas and Orlando have Archie Trammell’s radar course as an optional $185 add-on. All PROP seminars are free to registered attendees, sponsored by MHIA.