CHI07FA046

The airplane was established at a cruise altitude of 12,000 feet and the pilot did not report any problems during the en route portion of the flight. Upon initial clearance to descend from cruise altitude, the pilot advised the controller that he might have to stay higher due to ice. The pilot was subsequently cleared to 7,000 feet, instead of the initial 4,000 feet. About 15 miles from the destination airport, the pilot was cleared for a Global Positioning System (GPS) approach and instructed to maintain 3,900 feet until reaching the initial approach fix. The pilot subsequently inquired about descending lower and was cleared to 3,600 feet. The pilot commented that the airplane was "picking up some ice here, so we're trying to be real careful." Track data indicated that the airplane continued toward the airport, descending as low as 3,200 feet. However, about 2.25 miles from the airport, the pilot declared a missed approach, stating: "We're picking up too much ice." The flight was cleared to an alternate airport and instructed to climb to 5,000 feet. However, the airplane was unable to climb above 4,500 feet and the pilot reported that the airplane was still picking up ice. The pilot subsequently stated that he was unable to maintain altitude because of "more ice." He requested vectors out of the icing conditions, but the controller was not aware of any area being better regarding icing. The pilot noted he was "losing altitude now pretty good." The pilot selected an intermediate airport that was closer to his present position. The controller cleared the flight as requested and instructed the pilot to maintain 4,000 feet. The pilot replied, "All I can do is 4,000." Track data indicated that the flight was established on an east-southeasterly course, and passed about 0.6 miles south of the intermediate airport. It entered a left turn to a northeast course and passed the airport, apparently intending to return for landing. The airplane impacted trees and terrain about 1.75 miles northeast of the intermediate airport. A witness stated that the airplane came through the treetops, "nose dived into the ground" and spun around, before coming to rest. GPS altitude data revealed a steadily increasing descent rate after reaching 4,500 during the diversion to the alternate. Airmen's Meteorological Information (AIRMET) advisories for moderate icing were in effect. The AIRMET coverage area included the destination and alternate airports. The pilot obtained two pre-flight weather briefings during which he was advised of the AIRMET. Although, the AIRMET was updated after the briefings, the predicted icing intensity and geographical coverage area remained the same. A post accident inspection of the airplane did not reveal any anomalies consistent with a pre-impact failure or malfunction. Several ice fragments, consistent in appearance to rime ice, were observed on the ground at the accident site by initial responders. The fragments exhibited a contour approximately matching the profile of the wing leading edge. The Pilot's Operating Handbook stated that the airplane was not certified for flight into known icing conditions. The handbook advised that in the case of an inadvertent icing encounter, "evasive action should be initiated immediately when icing conditions are first encountered."

History of flight

On December 26, 2006, at 1100 central standard time, a Rockwell International Model 114, N55MB, piloted by a private pilot, was destroyed during an in-flight collision with trees and terrain near Jasper, Tennessee. The flight was operating under 14 CFR Part 91 on an instrument flight rules (IFR) flight plan at the time of the accident. The pilot and one passenger sustained fatal injuries. Two additional passengers sustained serious injuries. The personal flight departed Ottawa Executive Airport (Z98), Zeeland, Michigan, at 0742. The intended destination was Winchester Municipal Airport (BGF), Winchester, Tennessee. However, the flight had executed a missed approach at BGF and was in the process of diverting to Marion County Airport (APT), Jasper, Tennessee, at the time of the accident.

The pilot obtained preflight weather briefings at 0506 and 0638, the morning of the accident. The briefer informed the pilot of forecast icing and instrument conditions along the proposed route of flight and in the vicinity of the intended destination.

The flight departed Z98 and proceeded southbound, climbing to a cruise altitude of 12,000 feet mean sea level (msl). The pilot informed Grand Rapids Air Traffic Control Tower (ATCT) Radar Approach Control (Grand Rapids, Michigan) that the airplane picked up a "little bit of icing" in the climb. The flight leveled at 12,000 feet and proceeded on course.

At 1011, the flight established contact with Nashville ATCT Radar Approach Control (Nashville, Tennessee) and reported level at 12,000 feet. At 1020, the controller instructed the pilot to descend and maintain 4,000 feet. However, the pilot advised the controller that he might have to stay higher than 4,000 feet due to icing concerns. The controller subsequently amended the clearance to maintain 7,000 feet. Air traffic control (ATC) radar track data indicated that the flight was approximately 29 miles east of Nashville at that time and that the pilot began the descent to 7,000 feet promptly.

At 1027, control of the flight was transferred to Memphis Air Route Traffic Control Center (ARTCC). Upon establishing contact, the pilot reported descending through 9,600 feet with 7,000 feet assigned. The controller subsequently advised the pilot to expect the Global Positioning System (GPS) Runway 18 approach into BGF. At 1032:30 (HHMM:SS), the pilot was instructed to descend and maintain 4,000 feet. Radar track data indicated that the flight was approximately 31 miles north of BGF and was descending through 8,300 feet at that time.

At 1038:19, the flight was cleared for the GPS Runway 18 approach into BGF. The pilot was instructed to maintain 3,900 feet until crossing the initial approach fix (IAF), Boiling Fork Non-Directional Beacon (NDB). The flight was approximately 15 miles north of the airport, descending through 4,700 feet. The pilot inquired about descending lower, but the controller informed him that 3,900 feet was the minimum IFR altitude for the flight's current location. The controller noted that the minimum IFR altitude decreased to 3,600 feet about 5 miles ahead. The pilot replied that he would hold at 3,900 feet. Radar track data indicated that the flight leveled at 3,900 feet about that time. The track data indicated that radar contact was lost about 1042:17 as the airplane descended into BGF. The altitude associated with that data point was 3,800 feet.

A Memphis Center controller stated that radar coverage in the vicinity of Jasper was normally intermittent below 5,000 feet.

At 1042:22, the pilot inquired about descending lower. The controller cleared the flight to descend and maintain 3,600 feet until reaching Boiling Fork IAF. The pilot replied: "Okay, we're just picking up some ice here, so we're trying to be ... real careful."

GPS coordinate data indicated that the flight proceeded toward the airport, descending to approximately 3,200 feet at 1043:52. At 1044:06, the pilot informed the controller: "We're gonna go ahead and go missed now, we're picking up too much ice here." The flight was about 2.25 miles north of the airport. The controller instructed the pilot to execute the missed approach procedure and subsequently cleared the flight to Lovell Field Airport (CHA), Chattanooga, Tennessee, at 5,000 feet as requested by the pilot.

GPS coordinate track data indicated that the airplane over flew the airport and started a left turn toward CHA about 1045:20. The GPS altitude at that time was 3,933 feet. ATC radar track data suggested that radar contact was re-established about 0.75 miles east-southeast of BGF at 4,300 feet. The flight proceeded on an approximate magnetic course of 113 degrees toward CHA.

At 1047:39, the pilot informed the controller that the airplane was "still picking up ice" at 4,500 feet and inquired about cloud top reports. The controller replied that he did not have any top reports, but offered the pilot the option of climbing to 7,000 feet. At 1047:55, the pilot stated: "I'm trying to climb and I'm . . . actually not being able to. It looks now I'm gonna stay right where I'm at here . . . I'm not able to climb any longer . . . so I'm gonna have to just hold here I suppose."

At 1050:39, the pilot reported that he was not able to maintain 4,500 feet because of "more ice." He requested radar vectors to "some place warm or out of this ice." The controller asked, "You're not able to hold altitude?" and the pilot replied, "Affirmative we're losing [altitude] very slightly here at 4,400 [feet]." The controller informed the pilot that he was not aware of any area being better with regard to icing. The pilot replied, "Looking for . . . some place that has decent visibility so I can come down and get below it . . . cause I'm in the soup right now . . . and I'm losing altitude now pretty good."

At 1054:46, the controller inquired if the flight was out of the clouds and icing conditions. The pilot replied "Negative." The pilot elected to divert to APT, which was approximately 7 miles east of the airplane's position at that time. The controller subsequently cleared the flight for an approach to APT. The controller instructed the pilot to maintain 4,000 feet to the "radio beacon." The pilot replied, "All I can do is ... 4,000." The altitude clearance was amended to cruise at or below 4,000 feet. The controller informed the pilot that APT was at his eleven-thirty position and 4.1 miles.

At 1057:28, the controller released the pilot to the airport common traffic advisory frequency. At 1058:23, the pilot contacted the controller, but when the controller acknowledged, "go ahead," the pilot replied, "Nothin." No further communications were received from the accident airplane.

Radar track data indicated that after the missed approach at BGF, the airplane became established on a course toward CHA and climbed to 4,500 feet. However, altitude data suggested that about 1049:31, the airplane began a gradual descent until reaching 4,000 feet at 1055:32. This was the final data point associated with ATC radar. The flight was approximately 5.7 miles west of APT at that time.

GPS track data indicated that the airplane continued on an east-southeast course in a gradual descent. At 1055:33 the GPS recorded an altitude of 3,840 feet. At 1058:10, the flight was located about 0.6 miles south-southwest of APT at 2,866 feet (GPS altitude). About that time, the airplane entered a left turn toward the northeast. The final GPS data point was recorded at 1059:41, and indicated an altitude of 751 feet.

Review of the radar and GPS track data provided average descent rates as the pilot attempted to divert. Between 1049:31 and 1055:32, radar data suggested that the airplane descended 500 feet; an average rate of 83 feet-per-minute (fpm). Between 1055:33 and 1058:10, GPS data indicated that the airplane descended 974 feet; an average descent rate of 372 fp