Mitsubishi MU-2B-60 accident at Greenwood, Indiana, 11 Sept 1992

Accident narrative

On September 11, 1992, about 1457 central daylight time, a Mitsubishi MU-2B-60 and a Piper PA-32-301 Saratoga collided at 2,100 feet mean sea level approximately 2 miles northeast of the Greenwood Municipal Airport in Greenwood, Indiana. The PA-32 was descending en route to Greenwood Airport in accordance with visual flight rules. The MU-2, also operating under visual flight rules, was climbing out of Greenwood en route to Columbus, Ohio. The collision occurred in daylight visual meteorological conditions. The pilots of both airplanes and the four passengers aboard the MU-2 were fatally injured. The two other occupants of the PA-32 were seriously injured, and both airplanes were destroyed.

### The flights

The PA-32 departed Eagle Creek Airport about 1245 for a flight to Greenwood Airport, with an en route stop at Terry Airport. On board were the pilot, a pilot-passenger seated in the right front seat, and the pilot's daughter. The 54-year-old pilot held a private pilot certificate with an instrument rating and had logged more than 1,200 total hours, including approximately 150 hours in the PA-32. The pilot-passenger was also a qualified private pilot with an instrument rating.

The MU-2 had arrived at Greenwood Airport about 1400 from Huntingburg, Indiana. The 68-year-old pilot and four passengers boarded the airplane and departed shortly after 1430. The pilot held a commercial certificate, an instrument rating, and flight instructor certificates for single and multiengine airplanes. He had logged more than 19,000 hours of flight time, of which about 9,000 hours were in the MU-2. He had filed an instrument flight rules (IFR) flight plan for the leg to Columbus, Ohio.

### Sequence of events

At 1445:17, the PA-32 pilot advised the Indianapolis Departure West/Satellite controller that he had departed Terry Airport and would land at Greenwood. The controller radar-identified the airplane and instructed the pilot to climb and maintain 2,500 feet. Control was later transferred to the Departure East/Satellite controller. At 1455:51, the controller advised the PA-32 pilot that the airport was at twelve to one o'clock and three miles. The pilot confirmed he had the airport in sight. At 1455:57, the controller terminated radar service and approved a frequency change, which the pilot acknowledged.

At 1456:41, the MU-2 pilot contacted the Departure East/Satellite controller, stating he was "off the ground Greenwood standing by for clearance to Columbus." The controller issued a transponder code and instructed the flight to maintain 2,500 feet. There were no further communications with the MU-2.

Witnesses stated that the PA-32 was southbound, while the MU-2 was climbing and turning toward the east. They observed the PA-32 strike the MU-2's fuselage in the area of the empennage. The collision occurred about 1457 at an altitude of 2,100 feet.

Following the collision, the MU-2 was uncontrollable and crashed inverted in a residential area. The pilot-passenger of the PA-32 took control of the airplane and made a controlled descent for almost one mile before striking houses and coming to rest in a back yard, where a postcrash fire consumed the airplane.

### What the investigation found

The MU-2's empennage separated in flight. The left horizontal stabilizer and elevator were found in a cornfield west of the main tail section. Investigators noted three propeller slashes in the upper skin of the left horizontal stabilizer, and a transfer of gray paint onto the leading edge deice boot. The PA-32's propeller spinner was crushed and twisted, exhibiting blue paint transfers. All three of its propeller blades were missing sections from their tips and had blue paint transfers. The investigation found no evidence of an in-flight fire on either airplane.

Using recorded radar data, the Safety Board calculated the performance parameters of both airplanes in the 11 seconds prior to the collision. The MU-2 had an average ground speed of 168 knots, an average magnetic heading of 066 degrees, and an average vertical velocity of +1,596 feet per minute. The PA-32 had an average ground speed of 127 knots, a magnetic heading of 173.5 degrees, and an average vertical velocity of -390 feet per minute.

A cockpit visibility study was conducted to determine the probable locations of the airplanes as they would have appeared to each pilot. The study revealed that the PA-32 would have appeared below the horizontal zero eye reference plane, in the lower left corner of the MU-2's windshield, clear of all obstructions from 20 seconds before the collision.

Postmortem examinations found no preexisting medical conditions that contributed to the accident. Toxicological tests for both pilots were negative for ethanol and major drugs of abuse. The pilot of the PA-32 was incapacitated during the collision and died of smoke inhalation and burns. The occupants of the MU-2 died of multiple traumatic injuries sustained at ground impact.

### Probable cause

The National Transportation Safety Board determined that the probable cause of the accident was the inherent limitations of the see-and-avoid concept of separation of aircraft operating under visual flight rules that precluded the pilots of the MU-2 and the PA-32 from recognizing a collision hazard and taking actions to avoid the midair collision.

Contributing to the cause of the accident was the failure of the MU-2 pilot to use all of the air traffic control services available by not activating his instrument flight rules flight plan before takeoff. Also contributing to the cause of the accident was the failure of both pilots to follow recommended traffic pattern procedures, as recommended in the Airman’s Information Manual, for airport arrivals and departures.