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On August 22, 2000, at 2047 mountain standard time, a Bellanca 17-30 single engine airplane, N4905V, collided with mountainous terrain during a cruise descent 4.5 miles east-northeast of Scottsdale, Arizona. The airplane was destroyed and the airline transport pilot and passenger received fatal injuries. The airplane was owned and operated by the pilot as a personal flight under 14 Code of Federal Regulations Part 91. The flight originated from the Cal Black Memorial airport near Hall's Crossing, Utah, about 1900, and was en route to Stellar Airpark, Chandler, Arizona. A monsoonal weather system was rapidly moving through the area at the time of the accident producing instrument meteorological conditions near the accident site. A flight plan was not filed for the flight.
On September 1, 2000, a pilot spotted the wreckage on the southwestern slope of the McDowell mountain range and reported it to authorities. The airplane was located about the 3,000-foot level, about 200 feet below the ridgeline, which runs from the northwest to southeast. The location was identified as 33 degrees 38.560 minutes north latitude and 111 degrees 49.043 minutes west longitude, 4.5 miles east northeast of Scottsdale airport. The accident site lies on a direct route between the Cal Black Memorial Airport and Stellar Airpark.
The Federal Aviation Administration (FAA) reported that a review of Williams Gateway airport terminal radar showed a 1200 code secondary beacon return that was southbound on a direct heading toward Stellar Airpark. The radar data depicted the airplane descending from 7,000 feet to 3,000 feet msl. The radar track depicted the airplane turning toward the east at a point north of the Scottsdale airport, continuing in the turn until it disappeared from the scope at the same coordinates that corresponded to the crash site. The last radar reported altitude, heading, and groundspeed were 3,000 feet, 140 degrees, and 156 knots, respectively.
The airline transport pilot held ratings in single and multiengine airplanes. He also held a commercial pilot certificate for helicopters. He was employed as an airline pilot by American West Airlines. He was issued a first-class medical certificate on March 10, 2000, with a limitation indicating that he "must have available glasses for near vision." According to his last medical certificate application, he reported having had accumulated a total of 17,000 flight hours. The pilot's logbooks were not recovered during the course of the investigation. It is not known how many hours he had accumulated in the accident airplane.
The pilot's partner in the accident airplane stated that it was common for the pilot to stay below the floor of class B airspace (4,000 feet msl) while transitioning through the area en route to Stellar Airpark. He told investigators that it is frequently difficult for visual flight rules (VFR) traffic to get a clearance from controllers because of their high workload.
According to the aircraft co-owner, the 4-seat airplane was equipped with two visual omni range (VOR) navigational radios. A fuel slip from Midway Aviation at Cal Black Memorial Airport indicated that the pilot refueled with 22 gallons of aviation gasoline upon his arrival, August 15, 2000. Aircraft maintenance records were not located prior to this reports writing.
The partner told investigators that it was the pilot's usual practice to obtain a weather briefing from the Prescott flight service station (FSS). A review of services by FAA quality assurance personnel found no record of a weather briefing for the accident flight by either the flight service station system or through DUATS.
A witness at the destination airport reported that the weather system began moving through the area about 2000 on the evening of the accident. He described the system as being comprised of a large dust cloud approaching from the east-northeast followed by cumulus build-ups, heavy rain, and gusty winds. He stated that the system had essentially passed through the area by 2100.
A meteorology study was conducted by a National Transportation Safety Board staff meteorologist, and the following are details extracted from that study:
It was determined that the monsoon season (a seasonal reversal with a distinct wet season) started in the middle of June for the Phoenix, Arizona, area. On a typical day during the Arizona Monsoon, thunderstorms develop first in the early afternoon over the higher mountains and the Mogollon Rim. The thunderstorms move south and westward down the plateau along the topographic gradient. Rain cooled air from these thunderstorms, known as outflow, moves down from the high country and into the deserts. Acting like a small scale cold front, this outflow causes the hot and moist desert air to rise producing thunderstorms. Over the higher deserts of southeast Arizona, thunderstorms also develop over the higher terrain and move west to northwestward during the mid and late afternoon.
On most days thunderstorm activity ends altogether around midnight. During the monsoon season, the maximum thunderstorm activity typically occurs in the Phoenix area by 2200, as both areas of convection from the plateau and the southeast high desert areas intersect over the area. Severe weather often accompanies the summer monsoon season with downburst winds, intense cloud-to-ground lightning, and flash flooding are the most common type of severe weather activity; however, hail and small tornadoes are also possible.
At 1935, the National Weather Service (NWS) Radar Summary Chart depicted an area of thunderstorms and rain showers extending over southern California into northwest Arizona, an area of rain showers over northeastern Arizona, and an area of thunderstorms over southeastern Arizona. The thunderstorms over southeast Arizona ranged from intense to extreme intensity (NWS intensities 5 to 6), with radar tops to 47,000 feet msl. The cell movement over the area was reported towards the west-northwest at 8 knots.
The 2035 Radar Summary Chart continued to depict an area of intense to extreme intensity thunderstorms and rain showers over southern Arizona.
The closest airport to the accident site was Scottsdale Airport (SDL), which was located 4.5 miles west-southwest of the accident site at an elevation of 1,510 feet msl. The weather observations at the airport were as follows:
At 1945, the reported weather was wind from 250 degrees at 7 knots; visibility 40 statute miles; ceiling broken at 20,000 feet; temperature 35 degrees Celsius; dew point 12 degrees Celsius; and an altimeter setting of 29.87 inches of mercury.
At 2045, the reported weather was wind from 150 degrees at 12 knots; visibility 4 statute miles in a dust storm; ceiling broken at 15,000 feet; temperature 32 degrees Celsius; dew point 15 degrees Celsius; and an altimeter setting of 29.94 inches of mercury.
It should be noted that a dust storm is an unusual, frequently severe weather condition characterized by strong winds and dust filled air over an extensive area. A dust storm usually arrives suddenly in the form of an advancing dust wall, which may be miles long, and several thousand feet high, ahead of which there may be some dust whirls, either detached or merging with the main mass. Ahead of the dust wall the air is very hot an the wind is usually light.
The weather observation facility at Phoenix Sky Harbor International Airport (PHX), Phoenix, Arizona, located 18 miles southwest of the accident site, reported the following weather:
At 1956, the wind was variable at 3 knots; visibility was 10 statute miles; and there were a few clouds at 9,000 feet and broken cloud layers at 14,000 and 25,000 feet. The temperature and dew point were 36 and 14 degrees Celsius, respectively, and the altimeter setting was 29.85 inches of mercury.
At 2023, a special weather observation was issued indicating that the wind was from 170 degrees at 23 knots gusting to 28 knots; the visibility was 1.75 statute miles in haze and squalls; there were a few clouds at 2,000 feet, and scattered clouds at 8,000 feet in cumulonimbus clouds; ceiling broken at 12,000 feet; the temperature and dew point were 32 and 16 degrees Celsius respectively; and the altimeter setting was 29.90 inches of mercury. The remarks section of this special report indicated that the "pressure rising rapidly, present weather blowing dust, cumulonimbus clouds, with occasional lightning in-cloud east."
At 2031, another special weather observation was issued, which reported changes with the wind and visibility. The wind was from 160 degrees at 22 knots gusting to 33 knots, and the visibility was 2 statute miles in haze. The remarks section of this special observation reported that a wind shift was recorded at 2017, the pressure was rising rapidly, and reported that the present weather consisted of blowing dust and cumulonimbus clouds distant east with occasional lightning in cloud to the east.
There were additional special weather observations at 2043, 2056, and 2102, all of which stayed consistent with the aforementioned special reports, with slight changes to wind gusts and visibilities.
The Luke Air Force Base (LUF), located 28 miles west-southwest of the accident site reported the following conditions around the time of the accident:
At 2048, the wind was from 140 degrees at 21 knots gusting to 26 knots; visibility 1/2 statute miles in blowing dust; a few cumulonimbus clouds at 6,000 feet; ceiling broken at 15,000 feet and 25,000 feet; temperature 34 degrees Celsius; dew point 15 degrees Celsius; and an altimeter setting of 29.90 inches of mercury. The remarks section of this observation reported that the pressure was rising rapidly, and cumulonimbus clouds were in the distant northeast through east and 16 miles south moving north.
At 2055, the weather observation remarks reported peak winds from 120 degrees at 43 knots and frequent lightning in-cloud, cloud-to-cloud, and cloud-to-ground.
The closest Weather Surveillance Radar (WSR) was located at Williams Gateway Air Force Base, which was located 23 miles south-southeast from the accident site. Review of the radar data between 2013 and 2053 revealed convective radar returns near the accident site. In addition, there were lines of relectiveness prevalent up to 20 dBZ (color coded dark blue on WSR chart and equivalent to "very light" precipitation returns). The lines lead the convective activity and over time moved north and west bowing out in a concave shape. This feature is identified as an outflow boundary or a gust front, which was identified as moving through the accident site by 2048.
A gust front is formed when the down draft and rain-cooled air of a thunderstorm reach the ground, and then spread out along the ground. It is usually marked by a sudden wind shift, sharply falling temperatures, and possibly heavy downpours and/or hail. An outflow boundary is a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature. In both cases, additional thunderstorms can possibly build along the gust fronts or outflow boundaries.
The Geostationary Operational Environmental Satellite number 10 (GOES-10) data was reviewed in the infrared band for the time period between 2000 and 2100. The GOES-10 infrared satellite image at 2000, indicated that the accident site was located to the northwest of a large Mesoscale Convective System (MCS) that extended over southeast Arizona into New Mexico. At 2030, the MCS bordered the accident site with the highest and coldest cloud tops to the south and east of the accident site. The radiative temperature over the accident site corresponded to cloud tops between 32,000 and 42,000 feet.
A MCS is a complex of thunderstorms, which becomes organized on a scale larger than the individual thunderstorms, and normally persists for several hours or more. They may be round or linear in shape, and include systems such as tropical cyclones and squall lines.
The Arizona area forecast issued at 1939, indicated that there was a chance of "Widely scattered thunderstorms and light rain with cumulonimbus cloud tops to 40,000 feet."
There was an in-flight weather advisory issued around the time of the accident; however, there was no indication that the pilot attempted to obtain it. A Convective SIGMET was issued at 1955, and was valid until 2155, for an area that was to the southeast of the accident site. The outlook segment of the Convective SIGMET included the accident site area.
The terminal aerodrome forecast (TAF) for PHX issued at 1952, reported that between 2100 and 2200, temporary conditions could include wind from 150 degrees at 17 knots gusting to 35 knots; visibility 1 statute mile in blowing dust; and broken ceilings at 8,000 feet in cumulonimbus clouds. The PHX TAF was amended at 2022, and forecast temporary weather conditions between 2000 and 2200, which could include wind from 160 degrees at 20 knots gusting to 35 knots; visibility 1 statute mile in moderate rain and blowing dust; and ceiling broken at 8,000 feet in cumulonimbus clouds.
According to the United States Naval Observatory's Astronomical Applications Department, the sun set at 1905 mountain standard time, and the end of civil twilight occurred at 1931.
WRECKAGE AND IMPACT INFORMATION
The wreckage was not examined at the accident site by Safety Board investigators; however, recovery personnel reported that the accident site consisted of loose shale, sloping upward about a 45- to 50-degree angle. The wreckage was located within a 100-foot radius of the initial impact point. The airspeed indicator was found at the site with the needle impinged at the 160-knot point on the instrument face. The wreckage was transported to a secure facility in Phoenix, where it was examined on September 9, 2000, by a Safety Board investigator.
There was no emergency locator transmitter (ELT) signal reported at the time of the crash or at any time up to and including the time of recovery. Fragments of an ELT were found at the crash site.
The aircraft was severely fragmented with the cockpit/cabin area compressed into ball shape. The wings were fractured in multiple segments and the empennage, though intact, displayed impact damage. Flight control continuity could not be established due to the extent of damage.
The engine remained attached to the fuselage by one control cable. The engine case, cylinders, and oil sump were all damaged. The crankshaft flange was broken and the propeller was separated. The vacuum pump, both magnetos, the starter, oil cooler and alternator had all separated from the accessory case. The fuel pump and ignition leads were found broken and separated. The crankshaft would not rotate and it was noted that it was displaced to the right with the main oil seal popped out on the left side of the case. The oil screen was removed and was found clean.
The propeller hub was found broken into two pieces. One of the blades appeared slightly twisted toward a low pitch angle and there was light leading edge damage and chordwise scratching evident. The other propeller blade was fractured into three segments. The outboard tip was not recovered from the accident site. The other two segments displayed "S" bending, leading edge gouges, and chordwise scratches. The one segment was torn halfway through the blade in two areas.
Toxicological tests for ethanol and drugs were performed on the pilot's muscle tissue. The toxicological test was positive for 34 mg/dL of ethanol, 5 mg/dL of acetaldehyde, 1 mg/dL of n-butanol, 1 mg/dL of 2-butanol, and 12 mg/dL of isopropanol. The toxicology report indicated that, "the ethanol found in this case is from postmortem ethanol formation and not from the ingestion of ethanol." According to the Civil Aerospace Medical Institute's Forensic Toxicology Drug Information, the acetaldehyde, n-butanol, 2-butanol, and isopropanol are all byproducts of postmortem alcohol production and specimen putrefaction.