SEA00FA095

During climbout, the airplane encountered an area of freezing rain resulting in rapid airframe ice accretion and loss of climb capability. The pilot informed ATC that he was unable to maintain altitude and requested and received clearance back to Great Falls, the departure airport. ATC radar showed that the airplane then began a right turn over mountainous terrain extending up to 8,309 feet prior to loss of radar contact (lower and relatively flat terrain, down to less than 5,000 feet, was located to the left of the aircraft's track.) During the last minute of radar contact, the aircraft was in a right turn at a descent rate of about 400 feet per minute; the aircraft passed less than 1/2 mile from the 8,309-foot mountain summit just prior to loss of radar contact, at an altitude of 8,400 to 8,500 feet. The aircraft crashed on the southwest flank of the 8,309-foot mountain about 1/2 mile south of the last recorded radar position. Wreckage and impact signatures at the crash site were indicative of an inverted, steep-angle, relatively low-speed, downhill impact with the terrain. The investigation revealed no evidence of any aircraft mechanical problems.

History of flight

On May 31, 2000, approximately 1728 mountain daylight time, radio and radar contact was lost with a Cessna 414, N5113G, being operated by Lynch Flying Service of Billings, Montana, on a 14 CFR 91 company business flight from Great Falls, Montana, to Billings. The wreckage of N5113G was located the following day, June 1, 2000, at approximately the 7,500-foot level on the southwest flank of 8,309-foot Barker Mountain, approximately 37 nautical miles southeast of Great Falls and 6 nautical miles east of Monarch, Montana. The airplane was destroyed, and all three of the aircraft's occupants (the airline transport pilot-in-command, a prospective-hire commercial pilot undergoing a pre-employment screening flight with Lynch Flying Service, and a Lynch Flying Service pilot being repositioned from Great Falls to Billings and riding aboard the aircraft as a passenger) were found dead at the accident scene. Instrument meteorological conditions were reported at Great Falls at 1656 and 1756, and the flight (which departed Great Falls at 1711) was on an instrument flight rules (IFR) flight plan.

The accident flight was the return flight of a planned round trip from Billings to Great Falls and back. The purpose of the flight was to deliver another Lynch pilot to Great Falls to pick up another Lynch aircraft (a Cessna 402) and fly it back to Billings, and to pick up the pilot who had flown the Cessna 402 into Great Falls and return him to Billings. Additionally, the prospective-hire pilot was brought along on the trip to undergo a pre-employment screening evaluation. The pilot-in-command on the trip was Lynch's director of training (NOTE: Subsequent references to the "pilot" in this report are to the pilot-in-command, unless otherwise indicated.) The pilot who was delivered to Great Falls reported to the NTSB that on the flight to Great Falls, the pilot occupied the left seat, and the prospective hire occupied the right seat and flew the instrument approach into Great Falls. The Lynch pilot who rode to Great Falls also reported that the pilot told him that on the return flight to Billings, he intended to have the prospective hire occupy the left seat with the pilot-in-command in the right seat.

Lynch's chief pilot reported to the NTSB that the pilot utilized the WeatherMation computerized weather briefing service at Lynch during preflight planning. Recordings of FAA air traffic control (ATC) and air traffic services communications disclosed that prior to departing Billings, the pilot also twice contacted the Great Falls FAA automated flight service station (AFSS) and requested weather information. During the first contact, at 1321, the Great Falls AFSS preflight briefer advised the pilot that Great Falls was reporting 1/4 mile visibility in heavy snow and fog, and that an AIRMET advisory was in effect for occasional moderate rime and mixed icing conditions in clouds and in precipitation from 6,000 feet to flight level (FL) 180. The briefer also relayed a pilot report (PIREP) from a Cessna 340 aircraft indicating moderate rime ice at FL 190, along with the area forecast for Montana, the Great Falls terminal aerodrome forecast (TAF), and radar information showing light to moderate (with embedded heavy to very heavy) precipitation over most of the state. The briefer indicated that since the reported weather at Great Falls was worse than had been forecast (the visibility had been forecast to be 6 miles, with occasional visibility down to 2 miles, for that time period), he expected the TAF to be amended. The pilot stated that he "might have to try it", but indicated that he would wait and see if the visibility at Great Falls improved beyond 1/4 mile. He then filed an IFR flight plan for the Billings-Great Falls flight, with an estimated departure time of 1430 from Billings.

During the second contact, at 1516, the Great Falls AFSS briefer advised the pilot (who identified himself to the briefer as "Vince down at Lynch") of a convective SIGMET meteorological advisory for an area of thunderstorms around Billings. The pilot asked about any PIREPs of icing conditions. The briefer relayed PIREPs from Boeing 727 (B-727) and Beech Bonanza aircraft, which reported encountering light rime ice at 12,000 feet over Great Falls, and that at 15,000 feet, one of the aircraft had accumulated 1/2 inch of rime ice. The briefer also relayed to the pilot that he could expect to encounter shower activity almost immediately after departure from Billings, and that the precipitation would change to mixed rain and snow approximately 10 to 20 miles west of Lewistown. The briefer further stated that approaching Great Falls, the precipitation would change to light to moderate, and possibly heavy, snow showers. The pilot then revised his estimated time of departure from Billings to 1530, and also filed an IFR flight plan for the Great Falls-Billings flight. The pilot filed for a return flight departure time from Great Falls of 1700, with a cruising altitude of 17,000 feet.

The flight subsequently departed Billings, and at 1616, while en route to Great Falls, contacted the Great Falls AFSS by radio and relayed a PIREP. During this report, the pilot reported he was 71 miles southeast of Great Falls at 16,000 feet, that he was in and out of instrument meteorological conditions (IMC), that the temperature was -11 degrees C, and that he was not encountering any icing or turbulence. The Great Falls AFSS inflight briefer advised the pilot that the flight was north of the convective SIGMET area and relayed the weather conditions at and around Great Falls, including moderate precipitation south to southeast of Great Falls with upslope conditions prevailing in the vicinity. The briefer then asked the pilot if he needed updates to the AIRMETS for icing, and the pilot replied in the negative, stating that he had them.

Investigators interviewed the line service shift supervisor at Holman Aviation in Great Falls who was on duty at the time the accident airplane arrived. The shift supervisor reported that the aircraft arrived between 1630 and 1700, and remained on the ground for approximately 15 minutes. He stated that when the aircraft arrived, he observed approximately 1 inch of rime ice on the unprotected leading edge areas of the wing and tip tanks, and approximately 3/8 inch of ice on the aircraft's nose (he reported that the wing upper surfaces and deice boots appeared clean.) The shift supervisor stated that he removed a small amount of ice by hand from an area between the boot and the tip tank, and that he pointed out the ice to the crew, who replied with a statement to the effect of, "Yeah, we picked up some ice." The shift supervisor stated that the crew did not request that the aircraft be deiced, and that no deice fluid was applied to the aircraft before departure. The shift supervisor reported that the last time he saw the airplane, ice was still present on the airframe. Holman Aviation's president reported that while the crew was in the facility, he observed them looking at satellite weather in Holman's flight planning room (Holman Aviation subscribes to a weather briefing service provided by DTN, Inc.)

Investigators interviewed the Lynch pilot who rode to Great Falls in the accident aircraft (hereafter referred to as the "Lynch relief pilot".) This pilot reported that on the way in to Great Falls, the aircraft picked up about 1/2 inch of ice which was successfully removed with the deice boots. The Lynch relief pilot also stated that the aircraft was "sloughing ice" on the instrument landing system (ILS) final approach into Great Falls. The Lynch relief pilot stated that when the aircraft landed at Great Falls, the only ice he observed on the aircraft was the chunk the lineman picked off the aircraft, which the lineman handed to him. He stated that this piece was approximately 6 inches long and 1/2 inch thick. The Lyn