Grumann G-159, Linneus, Maine, July 19, 2000–Two pilots perished when an engine failed in night IMC about 2,000 ft above the aircraft’s single-engine service ceiling (“Accident Recaps,” September 2000, page 131). The NTSB determined probable cause to be “the pilot-in-command’s failure to maintain minimum control airspeed, which resulted in a loss of control. Factors in this accident were clouds, and a loss of engine power for undetermined reasons while in cruise flight above the airplane’s single-engine service ceiling.”
C-GNAK, a Gulfstream I operated by Airwave Transport, departed Moncton Airport (CYQM) in New Brunswick around 2348 EDT. En route to Dorval International Airport (CYUL) in Montreal the pilots reported to ATC “some pretty good icing” while climbing through 9,000 ft between 40 DME and 50 DME west of Moncton. They also reported some heavy rain but no thunderstorms. Later they clarified the icing as “moderate to severe” between 9,000 ft and 10,000 ft but said it lasted only “five minutes.”
The pilots leveled the GI at 14,000 ft and requested a block altitude between 14,000 ft and 15,000 ft. ATC gave the clearance at 0015:15 and told the pilots to contact Boston Center about a minute later. Checking in with Boston at 0017:54 they asked for and received “direct Dorval.” Not quite eight minutes later they requested a block clearance up to 16,000 ft, which they received. The crew declared an emergency at 0029:56 and asked for vectors for the nearest airport. They transmitted they could not maintain altitude and at 0030:10 they said they had lost control of the aircraft.
The Safety Board’s vehicle recorders division in Washington examined the 31-min tape from the cockpit voice recorder. About 15 min before the tape ended, the copilot said he was turning off the crossfeed from the right fuel tank to balance fuel. The CVR transcript indicates that the number-one engine stopped some 29 min into the recording. It further revealed that the pilots lost control a minute-and-a-half later, with the copilot questioning, “Which way are we flying?” The pilot later replied, “I have no idea which way is up.” Seconds later the recording stopped.
Investigators found the GI in a 25-ft diameter hole that was about five feet deep.
Airwave Transport was a commercial aviation company that was formed in 1991 and certified by Transport Canada. About 20 employees strong, the company specialized in nonscheduled freight air service from Toronto (CYYZ) and CYUL. At the time of the accident, it operated two GIs and a Convair CV-580.
The pilot on the accident flight was the owner and president of the company. He held a Canadian ATP for single- and multi-engine land airplanes and held an instrument rating. He was typed in the GI, Cessna 550 and Boeing 727. Airwave Transport reported that he had about 6,000 hr TT, with 500 hr PIC in the GI. He had completed recurrent training on the GI at FlightSafety International in October 1999. Additionally, he held an aircraft maintenance certificate for the Convair CV-580, Convair CV-640 and the GI.
The copilot had approximately 600 hr TT, 300 of which were in the GI. Airwave Transport hired him in May 1999 as a dispatcher and he began his transition to the GI in November 1999. He completed GI initial training at FlightSafety International on Dec. 10, 1999, and passed a pilot proficiency check in January last year. The copilot held a Canadian commercial pilot certificate for single- and multi-engine land airplanes and held an instrument rating. He also held a type rating for the GI.
Airwave Transport purchased this GI in November 1999 and maintained it according to an approved manufacturer inspection program. Maintenance personnel inspected the aircraft on July 10, 2000, and the owner test flew it on July 11 and July 15. A company dispatcher, who held a commercial certificate and had some training for the GI, accompanied the owner on the test flights and told the NTSB there were no discrepancies noted on the flights. He also recalled they tested the airborne weather radar and it worked properly.
Investigators found the left engine’s propeller in a “feathered or near feathered position.” They were unable to recover the right engine’s propeller hub; consequently the pitch of the right blades was uncertain. Metallurgical investigators found no evidence of torsional fractures or preexisting fractures within the engines that would provide the cause for a failure. The NTSB was unable to recover the engine-driven fuel pumps or boost pumps.
The GI was equipped with boots on the leading edges of the wings and horizontal and vertical stabilizers. The propeller blades, spinners and engine inlet areas were electrically de-iced.
Airwave Transport faxed a weather briefing package to the crew that included in-flight advisories, Pireps, winds- and temperature-aloft forecasts, weather observations and forecasts for selected Canadian and U.S. airports. Company representatives told the NTSB that this was normal procedure but that the crew was responsible for updating the information and had sole discretion for “go/no-go” decisions.
Satellite data issued at 0015 that day depicted an overcast layer of clouds across the flight path with tops between 14,000 ft and 26,000 ft. Investigators estimated cloud tops over the accident site at 19,000 ft. The Canadian Meteorological Center (CMC) issued Gander Sigmet Bravo at 0030, about the time of the accident, for “a broken line of cumulonimbus clouds with tops to 40,000 ft observed and forecast, with the potential for severe turbulence and severe clear icing.” National Weather Service records found no Pireps for icing or turbulence over Maine. A weather observation taken at nearby Houlton, Maine, at 0049 reported winds from 230 deg at five knots, visibility eight miles and ceiling 600 ft overcast. The temperature and dewpoint were matched at 14 deg C and the altimeter setting was 29.71.