N454MA

HISTORY OF FLIGHT

On August 4, 2005, approximately 0206 mountain daylight time, a twin-engine Mitsubishi MU-2B-60 turbo-prop airplane, N454MA, was destroyed upon impact with terrain near Parker, Colorado, while on an instrument approach to the Centennial Airport (APA), near Denver, Colorado. The instrument rated commercial pilot, sole occupant of the airplane, was fatally injured. The airplane was registered to and operated by Flight Line, Incorporated, of Watkins, Colorado. An instrument flight rules (IFR) flight plan was filed for the flight that originated at Salt Lake City International Airport (SLC), near Salt Lake City, Utah, approximately 0040. Night instrument meteorological conditions prevailed for the on-demand air cargo flight conducted under 14 Code of Federal Regulations Part 135.

A review of air traffic control communications revealed that the pilot received radar vectors to intercept the localizer course for the instrument landing system (ILS) RWY 35R approach and was instructed to maintain an altitude of 8,000 feet mean sea level (msl) until established on the localizer course. When the airplane was approximately four miles south of CASSE intersection (the final approach fix), an approach controller cleared the flight for the instrument approach. The pilot acknowledged the clearance and shortly after he was instructed to contact Centennial Tower.

At 0204:46, the pilot contacted Centennial Tower, but there was no response. He tried again at 0205:05.

At 0205:19, a tower controller responded and cleared the flight to land on Runway 35R. The pilot acknowledged. This was the last radio communication received from the flight.

A review of the radar data revealed an IFR target, positively identified as the accident aircraft, was approaching the airport from the southwest. The last two minutes of radar data revealed the flight was turning toward the north at an altitude of 7,900 feet msl at a ground speed of 140 knots.

As the flight approached CASSE intersection, the airplane was observed on radar descending to an altitude of 7,200 feet msl, while it remained at a ground speed of 140 knots. After crossing CASSE intersection, the airplane continued to track the localizer to the north, as it continued to descend below the glide slope until the data ended at 0206:36.

At 0206:40, a tower controller alerted the pilot to "...check altitude...your altitude indicates six thousand four hundred...you appear to be well below the glide slope." The pilot did not respond. The tower controller then made several attempts to contact the pilot but there was no response.

The last radar return was received approximately four miles south of the landing threshold of the runway at an altitude of 6,400 feet msl, still at a groundspeed of 140 knots, at approximately 39 degrees, 29 minutes north latitude and 104 degrees, 50 minutes west longitude.

The accident occurred at night in a remote area. There were no reported eyewitnesses to the accident.

PERSONNEL INFORMATION

The pilot held a commercial pilot certificate with ratings for single-engine land, multi-engine land, rotorcraft-helicopter, instrument airplane and instrument helicopter. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on January 6, 2005. At that time, the pilot reported having accumulated a total of 4,800 flight hours. The operator reported that the pilot flew approximately 70 hours per month, and had accrued approximately 1,200 hours in the same make and model.

According to the operator, the pilot's last Part 135 airmen competency-proficiency check was completed during March 2005.

AIRCRAFT INFORMATION

The Mitsubishi MU-2B-60 (s/n:1535SA) was a pressurized, high performance, twin-engine turboprop, which was configured to carry cargo at the time of the accident. Examination of maintenance records revealed that the airplane had undergone a 200-hour inspection on July 12-15, 2005. At that time, the airframe total time was 12,576.9 hours since new. The airplane had accrued 43.3 hours since the last inspection. The last one-year inspection was performed on September 30, 2004.

As of July 15, 2005, the left engine, a Honeywell TPE331-10-511M, had accrued a total of 9,074.9 hours since new, and 5,373.9 since overhaul. The engine had been installed on the airplane on December 12, 2004.

As of July 15, 2005, the right engine, also a Honeywell TPE331-10-511M, had accrued 12,910.4 hours since new, and 3,800.0 since overhaul. The engine was installed on the airplane on May 31, 2005.

METEOROLOGICAL INFORMATION

Weather reported at Centennial Airport, at 0153, was wind from 360 degrees at 9 knots, visibility 3 statute miles, rain, mist, scattered clouds at 800 feet, broken clouds at 1,600 feet, overcast ceiling at 2,500 feet, temperature 15 degrees Fahrenheit, dew point 14 degrees Fahrenheit, with a barometric pressure setting of 30.37 inches of Mercury.

Weather reported at 0205 was wind from 010 degrees at 8 knots, visibility 2.5 statute miles, rain, mist, ceiling broken at 1,000 feet, broken clouds at 1,600 feet, overcast ceiling at 2,200 feet, temperature 15 degrees Fahrenheit, dew point 14 degrees Fahrenheit, and a barometric pressure setting of 30.38 inches of Mercury. The ceiling was reported to vary between 600 to 1,300 feet. The tower visibility was reported as 4 statute miles.

Weather reported at 0211, was wind from 010 degrees at 7 knots, visibility 3 statute miles, rain, mist, scattered clouds at 700 feet, broken clouds at 1,200 feet, overcast at 2,200 feet, temperature 15 degrees Fahrenheit, dew point 14 degrees Fahrenheit, and a barometric pressure setting of 30.38 inches of Mercury. The tower visibility was reported as 4 statute miles.

Review of weather radar images taken between 0203 and 0208, revealed weak to moderate weather radar echoes in the vicinity of the accident site. Moderate to strong weather radar echoes were also present about 5 to 10 nautical miles south of the accident site. The tops of the echoes were reported at 30,000 feet.

AIDS TO NAVIGATION

The published inbound course for the ILS RWY 35R approach was 347 degrees magnetic, with the published DH decision height of 6,083 feet msl. The crossing altitude for the final approach fix (CASSE intersection) was 7,974 feet msl. The distance between CASSE and the missed approach point, which was the middle marker, was 5.9 nautical miles (nm). The middle marker was located 0.4 nm from the end of the runway. The airport elevation was 5,883 feet msl.

The published weather minimums for the ILS RWY 35R approach were a 200-foot ceiling and a half-mile visibility.

Following the accident, the FAA temporarily suspended use of the ILS RWY 35R approach procedure. After consulting with FAA Western Terminal Service Unit management, ILS operations were resumed at 0925. The next aircraft to fly the approach was instructed to report any discrepancies with the approach, and to immediately execute a missed approach if he noticed any unusual indications. The pilot successfully completed the approach at 0930, and reported no difficulties.

At 1420, FAA Technical Services personnel checked and recertified the ILS system as fully operational and within acceptable operational tolerances.

On August 6, 2005, the FAA conducted a post-accident flight check, which also found the ILS system to be operating normally and within acceptable operational tolerances.

AIR TRAFFIC CONTROL

A Safety Board Air Traffic Control (ATC) Specialist performed an investigation into the operational procedures and communications that transacted between the pilot, the Denver Terminal Radar Approach Control (TRACON) controller, and the Centennial Airport tower controller. The Specialist also examined the hardware and software utilized by these controllers to manage air traffic. The investigation included collecting information on the accident sequence, Minimum Safe Altitude Warning (MSAW) software adaptation documentation, reviewing air traffic controller training folders, and observing a radar replay of the airplane's approach into Centennial Airport.

According to the Safety Board ATC Specialist's Report, the approach controller stationed at the facility, which handled the accident airplane, had followed standard FAA procedures for vectoring the airplane to the ILS RWY 35R final approach course, and ensured that the pilot had the current weather information. The ILS glide slope intercept altitude was suitable, and should not have prevented the pilot from flying a stabilized approach.

The pilot reported receiving automated terminal information service (ATIS) information "Whiskey", which was the current and correct automated terminal information system (ATIS) broadcast. The controller also properly advised the pilot to expect the ILS RWY 35R approach, and vectored the airplane to intercept the ILS RWY 35R localizer on heading 020 degrees, which met the FAA standard for intercept angle.

A reconstruction of the accident sequence revealed that the pilot contacted the approach controller at Denver TRACON after entering the Denver area from the northwest. The pilot was vectored to the ILS RWY 35R final approach course and cleared for the approach about 0203. About a minute later, when the airplane was about 10 miles from the airport, the pilot was instructed to contact the tower at Centennial Airport. As the airplane continued inbound on the ILS approach, it descended below the glide slope. At 0205:37, the Denver TRACON MSAW visual alert and aural alarm activated for about 5 seconds and again from 0206:00 until terrain impact about 42 seconds later. The airplane was about 7.2 and 6.3 nm from the airport, respectively, when the MSAW alerts at Denver TRACON activated. Because of the MSAW software configuration at Denver TRACON, Centennial Tower was not eligible to receive aural MSAW alarms for any aircraf...