NTSB Factual Report

HISTORY OF FLIGHT

On January 6, 1997, at 2026 mountain standard time, a Piper PA-24-260, N9080P, was destroyed when it collided with terrain near Winston, Montana, after an in-flight breakup. The instrument-rated private pilot and his two passengers were fatally injured. The pilot had departed Billings, Montana at 1905, en route to Spokane, Washington, on an instrument flight plan, and was in cruise flight at 14,300 feet mean sea level, according to radar data. The pilot did not report any difficulties. About three sweeps of an ELT signal were noted by Air Traffic Control, but the ELT did not aid in locating the accident site. The aircraft burned after impact.

The pilot had departed Colorado earlier that day with a passenger, picked up another passenger in Wyoming, and had stopped in Billings to eat and refuel. He fueled the airplane with 38.3 gallons of 100 octane fuel, topping off the airplane's fuel tanks. At 1813, the pilot called the Great Falls AFSS by telephone and obtained a preflight pilot weather briefing for an IFR flight from Billings, Montana, via Victor 247 to Helena, then Victor 2 to Spokane, Washington. At 1825, he again called Great Falls AFSS and filed an IFR flight plan from Billings to Spokane.

At 1857, the pilot contacted Billings ground control and requested IFR clearance and taxi instructions. The pilot was issued an IFR clearance to Felts Field, Spokane, Washington, and taxied to runway 28R.

At 1905, N9080P was cleared for takeoff on runway 28R.

At 1908, N9080P was instructed to contact departure control.

At 1909, N9080P established radio contact with departure control, was given radar contact, and was cleared on course via Victor 247 at 10,000 feet.

At 1914, N9080P was told to contact Salt Lake Center on 127.75 mhz. N9080P reported on Salt Lake City ARTCC (ZLC) sector 15 frequency, level at 9000 feet.

At 1916, N9080P was cleared to climb to 11000 feet.

At 1936, N9080P was cleared to climb to 14,000 feet.

At 1938, N9080P was advised that radar contact was lost, and he was told to report 70 miles northwest of Billings.

At 1945, radar contact was reestablished with N9080P, 65 miles northwest of Billings. The pilot reported that his altitude was 13,800 feet.

At 1947, Sector 15 instructed N9080P to contact Salt Lake Center (sector 19) on 133.4 mhz.

At 1947:10, N9080P responded "one-three-three point..." The last portion of the pilot's frequency readback was blocked or cut off. There was no further communication with N9080P, despite repeated attempts by both Salt Lake Center sectors 15 and 19, including attempted relays by three other aircraft in the vicinity, and attempts by Helena approach control.

At 1953, eastbound Alpine Air flight 5031 reported seeing N9080P pass by after the Piper was declared as traffic.

At 2006:45, the sector 19 controller noted in communications with sector 15 that "I don't know where he's going...he's all over the place...."

At 2029, the sector controller being relieved briefed the relieving controller on N9080P, which was believed to be missing at that time; he noted that N9080P had not been flying the airway very well, and had also had difficulty holding his altitude, varying up to 300 feet above and below assigned altitude.

At 2034:37, Helena approach control advised the sector 19 controller that "we had a couple [sweeps] on an ELT that it only hit about three times and then it quit...."

In a written statement, the sector 19 controller stated that:

"I took a handoff from sector 15 on N9080P. The aircraft was on V247 at 140[00] feet. I was either on the land line or another aircraft stepped on him when I thought he tried to check on frequency. I then tried to answer him and give him the HLN [Helena] altimeter. After trying this a couple times with no response from N9080P, I tried to have sector 15 see if he was still on their frequency. I noticed that he had started to deviate south of course about 40-50 miles east of HLN. I then had PPS400 try to raise N9080P. PPS400 had no luck. PPS400 was approx. 5 west of HLN at 100[00] feet. Sector 15 advised that they were unable to contact N9080P and they had also tried to relay through another aircraft. I continued to observe N9080P deviating south of course then he corrected back a little bit and then deviated south again, sometimes as much as 90 degrees. I then alerted the supervisor and also HLN Approach in case he would come on their freq[uency]. Then approximately 10 southeast of HLN radar contact was lost in an area of normally fair radar. I advised the supervisor and was relieved from the sector. During this period I would try to contact N9080P about every 2-3 minutes on BTM, GTF, and QLS transmitters. His altitude was varying by about +400 ft high down to 140[00], but I did not notice him dropping below 140[00]."

Some aircraft wreckage was located about 1247 on January 7, 1997, by the Broadwater County Search and Rescue. The main wreckage was spotted from the air about 1504. Officers arrived on the scene at 1525 and determined that there were no survivors.

A portable oxygen bottle, with its regulator broken off, was found in the wreckage distribution path during the on-scene investigation. The oxygen bottle's regulator was not found until May 13, 1997, during a separate search of the accident scene, after snow melt. The shut-off valve on the regulator was damaged and could not be rotated. The position of the shut-off valve indicated that the valve was on at the time of the accident. The regulator had four connectors for oxygen masks or cannulas. Two of these connectors were capped with red dust covers. The other two connectors were clean and showed no visible damage; no evidence was found that indicated that masks or cannula bayonet-type connectors had been attached to the oxygen bottle regulator during the accident.

The pilot was part-owner of a Piper PA-24 that was not available to the pilot for this trip due to mechanical problems. The pilot's partner was interviewed by an FAA inspector; he stated that the pilot had rented N9080P due to the lack of availability of their airplane for maintenance reasons. He stated that the oxygen bottle had been borrowed from their aircraft for the flight and had been full of oxygen; four masks and two cannulas were also available.

In his statement, the pilot's partner noted that the pilot felt comfortable flying at altitudes above 12,500 feet without using oxygen. He related the pilot's statement that he had been flying in Mexico at 17,000 and did not use the oxygen he had on board, and had not felt any ill effects. He also noted that he had flown with the pilot on trips across the Rocky Mountains where they went to 14,000 feet on short duration flights and the pilot had not used oxygen.

Also in his statement, the pilot's partner noted that the pilot was under a lot of stress, in that a recent return trip from Mexico was delayed because of mechanical problems with their airplane, delaying departure of the accident flight. He noted that this business trip [the accident flight] was extremely important to the pilot as a large construction contract hinged upon its outcome.

PERSONNEL INFORMATION

The pilot received his private pilot's certificate with single-engine land rating in October 1976, and successfully accomplished a multi-engine rating in March 1978. He successfully accomplished an instrument-airplane rating in July 1978, on his second attempt, with 390 hours total flight time.

On his class three airman's medical certificate exam of March 11, 1993, the pilot had reported light flashes in his left eye, which was cited in his medical records of July 12, 1992, as vertical temporal light flashing lasting a second. He reported 3015 hours total pilot time on the March 11 medical application. He reported 2300 hours total flight time on his class three medical certificate application of June 20, 1995. In a May 27, 1993, letter to Audie W. Davis, MD, FAA medical examiner, he noted that he had vascular trouble that occurred at age 14; an item that had been recorded as abdominal varicosities on his November 28, 1990, class three airman's medical exam.

AIRCRAFT INFORMATION

The rented airplane was equipped with GPS, ADF, DME, nav-comms, and encoding altimeter. FAA Form 337 records indicated previous damage history. Static system, altimeter calibration and transponder check were completed June 21, 1996. An annual inspection had been completed on June 4, 1996, at 3583.6 hours total time.

METEOROLOGICAL INFORMATION

Forecast weather for the period during which the flight was conducted for reporting points in the vicinity was:

Billings, Montana: winds 240 at 16 knots gusting to 26 knots, 6 statute miles visibility, 10,000 broken becoming 7000' scattered, 10,000 overcast

Livingston, Montana: winds 240 at 25 gusting to 35 knots, 6 statute miles visibility, 5000' scattered, 8000 broken.

Helena, Montana: winds variable at 5 knots, 6 statute miles visibility, 4000' scattered, 7000' overcast.

Bozeman, Montana: winds variable at 5 knots, six statute miles visibility, 5000' scattered, 8000' overcast.

There were two pilot reports (PIREPS)in the general geographic area on the evening of the accident:

Light rime icing was reported by a MD-80 on descent between 16000' and 15000', 30 miles west of Billings at 2338.

Light rime icing was reported by a Boeing 727 at 15000', fifty miles northwest of Billings at 2055.

An FAA inspector interviewed a local pilot who had been flying a UH-60 in the geographic area on the evening of the accident. The pilot reported he flew at 10,000 feet MSL, where the outside air temperature was -10 degrees C. He encountered a trace of airframe ice out of Bozeman. About five minutes after passing Townsend, Montana, en route to Helena, he encountered moderate icing. He accumulated 1 inch to 1.5 inches of ice; 3/4 inches still remained after landing. Time of the occurrence was reported as 1850.

WRECKAGE AND IMPACT INFORMATION

The main wreckage was located in a valley between higher mountain ranges in rolling mountains with open vegetation, approximately seventeen nautical miles southeast of the Helena VOR, at 46 degrees 29.215 minutes north, and 111 degrees 36.015 minutes west. The wreckage was distributed over about two miles, on a scatter path of approximately 275 degrees magnetic from the first piece of wreckage--a fragment of the left aileron--which was found near the shoreline of Canyon Ferry Lake, which is at 3797 feet MSL. The main wreckage, including the main fuselage, aft fuselage, engine, propeller, and the inboard portions of both wings, were at 4100 feet MSL, about two miles from the shoreline of the lake. The wings stubs contained the left and right main fuel tanks. The main cabin was found in the inverted position. Post-impact fire consumed the main cabin, instrument panel, wing roots, and the accessory section of the engine.

Separated components of the aircraft were identified by GPS fixes by an FAA inspector, as noted:

Fuselage, engine and propeller 46 degrees 29.74 N 111 degrees 38.41 W Aircraft papers (blueprints) 46 degrees 29.26 N 111 degrees 36.20 W Oxygen bottle 46 degrees 29.20 N 111 degrees 36.19 W Wing spar material 46 degrees 29.26 N 111 degrees 35.37 W Left wing fragment 46 degrees 29.27 N 111 degrees 35.30 W Right wing fragment 46 degrees 29.27 N 111 degrees 35.16 W Left wing fragment with stall vane 46 degrees 29.25 N 111 degrees 35.01 W Vertical stabilizer 46 degrees 29.18 N 111 degrees 34.98 W Right stabilizer 46 degrees 29.20 N 111 degrees 34.58 W Vertical stabilizer fairing 46 degrees 29.17 N 111 degrees 34.71 W Left stabilizer 46 degrees 28.79 N 111 degrees 34.24 W Left wing fragment 46 degrees 29.27 N 111 degrees 34.27 W Left aileron fragment 46 degrees 29.29 N 111 degrees 34.01 W

During the on-site investigation, a portion of the left aileron, and the oxygen bottle regulator, were not located. These items were located by Helena FSDO personnel during a May 13, 1997, return trip to the accident site.

After completion of the on-site investigation, the wreckage was recovered and moved to Bozeman, Montana, where a post-salvage layout and reexamination were conducted on January 9, 1997.

The right and left wings were found fractured in two locations on each wing. A diagram of the wing fracture locations is attached to this report. It was noted that the left wing had undergone repairs prior to the accident. This wing sustained complete fractures at 7 feet 5 inches and 11 feet 10 inches outboard of the aircraft centerline. The left main spar, inboard of the 7' 5" fracture, remained attached to the main fuselage and was deformed and partially separated by post-impact fire. The fracture at 11' 10" displayed downward bending and leading edge downward rotational bending of the wing tip. The fracture occurred in the vicinity of the repaired portion of the left main spar. The left wing fuel tank was completely consumed by fire. The left main landing gear appeared to be retracted.

The outboard half of the left aileron, which was the first item found along the wreckage distribution path, separated at the hinges. The left aileron balance weight was not found at the accident site. Evidence of separation of the balance weight was found on the trailing edge of the left wing. The left aileron cable was separated at about the one-third span point in what appeared to be tension overload. Left aileron control continuity to the control column was established. Maintenance documents later noted that this aileron was re-skinned in June, 1995. The other half of the left aileron was later recovered by the FAA.

The right wing sustained fractures at 5' 4" and 8' 11" outboard of the fuselage centerline. The right main spar, inboard of the 5'4" fracture, remained attached to the main fuselage and was deformed and partially separated by post-impact fire. The main-spar fracture at the 5'4" location appeared to be upward. The fracture at 8'11" appeared to have sustained upward and downward forces during the separation. The separated right wing tip sustained deformation along the leading edge that appeared to match deformation found on the separated right stabilizer half. The right aileron remained attached to the aileron hinges with the aileron balance weight intact. The right aileron control cables maintained continuity, other than separation near the wing root. The right wing fuel tank was consumed by fire. The right main landing gear appeared retracted.

The aft fuselage and portions of the left and right sides of the stabilator were located together with the main fuselage at the accident site. The aft fuselage section, about aft of the baggage door, appeared to have separated from the forward section prior to impact; however the rudder and elevator cables remained intact, with impact damage and fire damage, and continuity to the pilot control column.

The inboard 3' of the leading edge of the stabilator appeared rotationally deformed in an up and aft direction; additionally, the main spar of the left side of the stabilator was fractured abut 14" outboard of the aircraft centerline. The outboard portion of the left stabilator was the third item along the wreckage distribution path.

The main spar of the right side of the stabilator was fractured about 3' outboard of the aircraft centerline. The right side of the stabilator displayed deformation similar to that of the left leading edge of the stabilator. Signatures were found on the right side inboard leading edge deformation that indicated that they were impacted by the leading edge of the right wing tip after the deformation occurred. Witness marks matching marks on the right wing-tip were noted near the fracture location on the right stabilator.

Stabilator and rudder control stops appeared undamaged. The vertical stabilizer and rudder separated from the aft fuselage and were found about midway along the wreckage path. The front mount of the vertical stabilizer was bent aft; the rudder remained attached to the vertical stabilizer at the hinges.

The Lycoming powerplant was inspected both at the accid

NTSB Probable Cause

Pilot incapacitation due to hypoxia. Failure of the pilot to use available oxygen is a factor.