NTSB Factual Report

HISTORY OF FLIGHT

On August 3, 2006, approximately 0925 mountain daylight time, a Piper PA-24-180 Comanche, N5416P, piloted by a private pilot, was destroyed when it collided with mountainous terrain during descent about 16 miles northwest of Mosca, Colorado, near the Great Sand Dunes National Monument. Visual meteorological conditions prevailed at the time of the accident. The cross-country flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91. A visual flight rules (VFR) flight plan had been filed but had not been activated. The pilot was fatally injured. The personal flight originated at Pueblo, Colorado, at 0837, and was en route to Alamosa, Colorado.

The pilot was the president of Pueblo Community College. According to the college, he was flying to Alamosa to have some work done on his radios. From there, he planned to fly to Durango, Colorado, and then drive to Cortez, Colorado, to attend the opening of a new college office.

At 0710, the pilot contacted the Denver Automated Flight Service Station (AFSS) and filed a VFR flight plan. According to a statement from the AFSS quality assurance specialist, most of the pilot's dialogue was unreadable due to equipment problems. Her summary report and a transcript of the weather briefing indicated the pilot was told, "VFR flight [is] not recommended due to an AIRMET (Airmen Meteorology Information) for occasional IFR (instrument flight rules) conditions until 1800Z (1200 MDT)." Another current AIRMET forecast mountain obscuration through 1300 MDT. At the time of the weather briefing, current weather conditions had not been loaded into [computer] system, so the briefer gave the pilot the previous hour's observations: Pueblo, Alamosa, and LaVeta reported VFR conditions. At the conclusion of the briefing, the pilot said: "I'll go ahead and give it a shot."

According to the flight plan, the route of flight was from Pueblo direct to Silver West Airport (C08), Westcliffe, Colorado, and then direct to Alamosa. Altitude and speed were listed as 10,500 feet and 125 KTAS (knots true airspeed), and estimated time en route and fuel on board were 1 hour, 15 minutes, and 5 hours, 30 minutes, respectively.

Taxi clearance to runway 26L came at 0829:35, and takeoff clearance was issued at 0837:20. The pilot contacted Pueblo departure control at 0839:25, and advised he was climbing through 6,500 feet. The last radio contact with the airplane was at 0856:27, when the pilot acknowledged that radar services had been terminated.

A Bureau of Land Management (BLM) surveyor, located about two miles from the accident site, said he heard an approaching airplane. He said the engine was "sputtering, like it was missing." He did not see the airplane, but he did hear a loud "pop." He went to a clearing and saw a fire on the mountainside. He telephoned his dispatcher in Pueblo, and gave his GPS (Global Positioning System) location and bearing to the fire. The witness was later questioned via telephone. He said the sound of the airplane seemed to be coming from the southeast and moving northwest. The sky was overcast and the mountaintops were obscured. He estimated the point of impact to be 500 feet below the overcast. The coordinates he gave his dispatcher were 37 degrees, 51'29.9" North latitude, and 105 degrees, 26'11.6" West longitude. The accident site was on a bearing of 265 degrees and approximately 2 miles from his position.

At 1000, the Denver AFSS received a call from the U.S. Forest Service, advising of a possible aircraft accident near Medano Pass. At 1520, Pueblo Air Traffic Control Tower (ATCT) received a telephone call from Pueblo Community College, indicating Alamosa, Durango, and Cortez airports had been contacted, and N5416P had not arrived. At 1550, the Denver AFSS also received a telephone call from Pueblo Community College, advising that N5416P had not arrived at Alamosa as planned. Search and rescue was initiated, and an ALNOT (alert notice) was issued at 1613. At 1704, Denver AFSS received a call from the college, advising that the Colorado State Department of Public Safety and the State Emergency Management Department was being activated, and at 1757, Pueblo Air Traffic Control Tower (ATCT) issued a similar ALNOT. At 1805, the Saguache County Sheriff's Department reported having found the wreckage. Denver AFSS cancelled their ALNOT at 1815, and Pueblo ATCT cancelled their ALNOT at 1822.

The accident occurred during the hours of daylight at a GPS location of 37 degrees, 51.167 North latitude, and 105 degrees, 27.633 West longitude, or about 30 DME (Distance Measuring Equipment) from the Alamosa (ALS) VORTAC (Very High Frequency Omnidirectional Radio Range) on the 030-degree radial.

PERSONNEL (CREW) INFORMATION

The pilot, age 54, held a private pilot certificate with an airplane single-engine land rating, dated May 21, 2004. He was not instrument rated. He also held a third class airman medical certificate, dated March 16, 2005, with the restriction, "Must wear corrective lenses." When he applied for this medical certificate, he estimated his total flight time to be 165 hours, of which 47 hours were accrued in the previous six months.

A reconstructed portion of the pilot's first logbook, his complete second logbook, and various airplane tax papers were submitted to establish the pilot's aeronautical experience, to wit:

From reconstructed logbook:

First flight, 02/08/03

Last flight, 03/22/03

Cessna 172, 13.5

Total flight time, 13.5

From second logbook:

First entry, 05/19/04

Private pilot practical flight test, 05/21/04

First flight, Piper PA-24-180, 06/11/04

Total flight time, 125.2

Pilot-in-Command, 32.4

Single-engine land, 125.2

Complex, 19.4

Mountain, 22.7

Night, 8.8

Last entry, 08/01/04

From tax papers:

Hours flown, N5416P:

September-December 2004 7.2

2005 96.5

January-July 2006 32.3

From these documents, it was estimated the pilot had accrued a total of 261.2 flight hours, of which 152.8 hours were in the Piper PA-24-180, and 136 hours were in N5416P.

AIRCRAFT INFORMATION

N5416P (s/n 24-270), a model PA-24-180, was manufactured by the Piper Aircraft Corporation in 1958. It was equipped with a Lycoming O-360-A1A engine (s/n L-1016-36), rated at 180 horsepower, driving a Hartzell 2-blade, all-metal, constant speed propeller (m/n HC-C2YR-1BF).

The airplane's maintenance records were recovered from the wreckage. According to these documents, the airframe, engine, and propeller underwent annual/100-hour inspections on October 29, 2005, at a tachometer time of 341.05. The original airframe and engine logbooks had been lost, but the airframe and engine total time-in-service was computed to be 2,909 hours. The engine was last overhauled on March 15, 1977, at a total time-in-service of 2,568 hours. It received a top overhaul on October 21, 1984, at 2,647 hours time-in-service.

A new propeller was installed on July 12, 2001, at a tachometer time of 217.97 hours. At the time of the last annual/100-hour inspection, it had accrued 123.08 total hours.

On August 31, 2004, the pitot-static system, altimeter, transponder, and encoder were tested in accordance with FAR 43, appendices E and F, and were certified for IFR (instrument flight rules). The most recent weight and balance were done on September 8, 2002, at a tachometer time of 224.2 hours (2,792.2 hours time-in-service).

METEOROLOGICAL INFORMATION

When the pilot took off from Pueblo Municipal Airport (PUB) at 0834, weather reported by AWOS was as follows:

0853: Wind, calm; visibility, 10 statute miles (or greater); ceiling, 1,000 feet broken; temperature, 19 degrees Celsius; dew point, 13 degrees Celsius; altimeter, 30.23 inches of Mercury; sea level pressure, 1017.7 mb.

At the time of the accident, weather recorded at the La Veta Mountain AWOS (VTP), located 37 miles south of the accident site, was as follows:

0937: Wind, 080 degrees at 13 knots, gusting to 19 knots; visibility, 10 statute miles (or greater); sky condition, 600 feet scattered, 1,200 feet scattered; ceiling, 7,500 feet broken; temperature, 15 degrees Celsius (C.); dew point, 9 degrees C.; altimeter, 30.54 inches of Mercury.

At the time of the accident, weather recorded at Alamosa (ALS), his destination, was as follows:

0952: Wind, calm; visibility, 10 statute miles or greater; sky condition, clear; temperature, 16 degrees Celsius; dew point, 9 degrees Celsius; altimeter, 30.37 inches of Mercury; sea level pressure, 1019.9 mb.

WRECKAGE AND IMPACT INFORMATION

The accident site was at a GPS elevation of 11,589 feet msl (above mean sea level). Ground scars indicate the airplane struck the mountain in a wings level, nose slightly low attitude, on a magnetic heading of 250 degrees. It then slid downhill approximately 75 feet, coming to rest on a magnetic heading of 293 degrees. There was no evidence of tree strikes. Terrain slope, as measured by an inclinometer, was 28 degrees. The airplane and surrounding vegetation caught fire and eventually burned out. The landing gear and flaps were both retracted.

MEDICAL AND PATHOLOGICAL INFORMATION

At the request of the Saguache County coroner, an autopsy and toxicology was performed on the pilot by the El Paso County Coroner's Office. According to their report, the pilot's death was attributed to "multiple blunt traumatic injuries." Toxicology protocol revealed the presence of caffeine. The specimens were unsuitable for testing for carbon monoxide.

TESTS AND RESEARCH

On September 8, the wreckage was recovered from the mountain and transported to Beegles Aircraft Service, Greeley, Colorado. On October 11, the engine was disassembled and examined. No anomalies were noted. There was camshaft and crankshaft continuity, and all connecting rods were attached. The carburetor, which had separated from the engine, was examined. The bowl was empty, and the throttle valve was closed. Both the engine-driven and auxiliary fuel pumps were destroyed by fire.

Examination of the airframe confirmed that the landing gear and flaps were retracted. The elevator trim tab was in the neutral position.

A Lowrance Electronics GPS (Global Positioning System) receiver was recovered from the wreckage and sent to the company in Tulsa, Oklahoma, for evaluation. According to Lowrance, data was downloaded from the memory chip, but the data was "garbled and unusable."

The Carburetor Icing Probability Chart was consulted. The temperature and dew point recorded at La Veta Mountain were conducive to "serious icing at cruise power." The temperatures and dew points recorded at Pueblo and Alamosa were conducive to "serious icing at glide power" (see Exhibits).

ADDITIONAL INFORMATION

In addition to the Federal Aviation Administration, parties to the investigation included the New Piper Aircraft Corporation and Textron-Lycoming.

The wreckage was released to the insurance company on October 11, 2006.

NTSB Probable Cause

a non-mechanical partial loss of engine power due to carburetor ice, and the pilot's failure to maintain clearance from terrain. Contributing factors in this accident were weather conditions conducive to carburetor icing and the pilot inadvertently flying into instrument meteorological conditions.