N8261J

HISTORY OF FLIGHT

On September 8, 2002, about 1135 mountain standard time, a Beech A36, N8261J, descended from cruise altitude and collided with terrain about 20 miles west of Grand Canyon, Arizona. The private pilot/owner operated the airplane under the provisions of 14 CFR Part 91. The pilot was fatally injured, and the airplane was substantially damaged. The personal flight originated at Bullhead City, Arizona, at 1047, and was destined for Liberal, Kansas. Visual meteorological conditions prevailed at the departure point, and an instrument flight rules (IFR) flight plan had been filed.

The pilot contacted the Prescott Automated Flight Service Station (AFSS) between 0941 and 1008 on September 8, 2002, to file an IFR flight plan and to obtain a standard weather briefing. The briefer provided a synopsis of current conditions, a description of the weather radar, the in-flight advisory for icing conditions, the route forecast, and winds aloft data. The transcript of that briefing is included in the docket for this accident.

The AFSS briefer advised the pilot that "the worst of your flight, as far as the weather is going to be right through Arizona and the western section of New Mexico." Regarding the current radar image the briefer advised the pilot that "north of Kingman and north of Winslow, right now there is a fairly sizable echo return of precip17 its been a kind of broken band of precipitation all day long, like I say extending from the southwest to the northeast section of the state." The pilot acknowledged that and the briefer advised, "..you'll probably have to go through that at some point, right now it looks like light to occasionally moderate precip in that area and then there's another fairly sizeable return that is just to the east of Farmington." The pilot acknowledged. The briefer then advised "...you can count on having some precip whether it's the one I'm discussing with you or something else moving in (over the northern Arizona)." The briefer gave the pilot the current AIRMETs in effect and stated, "...also of a concern is one for icing and they're calling for light to occasional moderate rime in clouds from 15,000 to 24,000 (feet)..." The pilot acknowledged and the briefing continued with the other en route and destination forecast and ended at 0957 after the pilot filed his IFR flight plan with a cruising altitude of 17,000 feet.

The Federal Aviation Administration (FAA) Los Angeles (ZLA) Air Route Traffic Control Center (ARTCC) transcripts of radio communications from 1046 through 1137 between the facility and the accident airplane were reviewed.

At 1046, N8261J contacted ZLA Sector-6 (R-6) after departure from Bullhead City and requested an IFR clearance to Liberal, Kansas, which the controller issued. The pilot then reported climbing through 11,000 feet at 1051. Three minutes later the pilot requested higher altitude and was cleared to 15,000 feet.

At 1101, the R-8 sector controller broadcasted Convective SIGMETs 30 for western Utah and Nevada, SIGMET 31 for western Arizona, and SIGMET 32 for western New Mexico and Arizona.

The flight was cleared to climb to 17,000 feet at 1104 and the pilot subsequently requested 19,000 feet at 1110, and the controller cleared the flight to the higher altitude.

At 1112, the pilot requested left deviation. The controller approved left deviation and cleared the flight direct to Liberal, Kansas, when the pilot was able. One minute later the pilot requested 21,000 feet and the controller approved the higher altitude.

The controller called N8261J at 1124, and the pilot reported "I really went through some bad turbulence here." The controller acknowledged the communication and then asked the pilot what his heading was and he advised "...270 (degrees) right now, I'll get back on course here in a minute." The controller then called traffic out to the airplane and asked the pilot if he was still descending or going back up. The pilot advised, "I'd like to go back up...but I'm still in the soup here." The controller advised the pilot that if he needed to change altitude and heading in the future, to let them know before he did it. There was no response. The recorded radar data showed the onboard transponder signal then went into a coast mode followed by a primary target only. Subsequently, an emergency locator transmitter (ELT) beacon signal was received. The wreckage was located on the Grand Canyon Vortac 265-degree radial at 21 nautical miles.

Review of the recordings disclosed that at 1145, during a position relief briefing, the R-8 controller advised the relieving controller that N8261J was getting into some weather, and had deviated north, made a U-turn and gone down to about 19,000 feet. The controller stated that N8261J had started going back on course and then disappeared.

PERSONNEL INFORMATION

According to the private pilot's logbook, he had accumulated about 2,124 total flight hours, with about 557 hours in the Prop-Jet Bonanza. The log showed 415 hours of instrument flight time and documented a flight review in compliance with the requirements of 14 CFR 61.56, occurring on October 2, 2000. His most recent second-class flight physical occurred on July 9, 2002.

AIRCRAFT INFORMATION

According to airframe logbook information, the most recent annual inspection occurred on December 5, 2001, at 1,036 total airframe flight hours.

The airplane had been modified by replacing the Continental TSIO-520 engine with a Allison 250-B17 turboprop engine. The airplane was also equipped with a WX1000 Stormscope, thunderstorm avoidance system.

METEOROLOGICAL INFORMATION

A National Transportation Safety Board staff meteorologist conducted a study of the weather conditions as forecast and existing at the time of the accident. The study is included in the docket for this accident. In summary, the meteorologist found the following.

The closest upper air or rawinsonde observation was from the Flagstaff NWS Office, located approximately 50 miles southeast of the accident site. The 1200Z sounding on September 8, 2002, along with the observed and derived stability parameters indicated a moist low-level environment through 500-mb, with the relatively humidity exceeding 90 percent several times between the surface and cruising level of the accident airplane at 21,000 feet. The freezing level was identified at 611-mb or approximately 14,000 feet and had a relative humidity of 88 percent.

The wind profile indicated a surface wind from the southwest veering to the southwest and increasing in wind speed with height. The rawinsonde wind information was lost above 300-mb or approximately 30,000 feet with wind speeds of 69 knots. The accident airplane was last observed at 21,000 feet and the sounding indicated wind at that level was from 200 degrees at 41 knots, with a temperature of -11.7 degrees C. Immediately below this level at 488-mb or approximately 19,800 feet, a strong shear layer was noted with a 11.1 knot per 1,000 feet change in wind speed with a Richardson number (Ri) of 0.4, which indicated a probability of severe clear air turbulence (CAT). This layer also had a high relative humidity of 92 percent and a threat of light rime type icing with a liquid water content (LWC) of 0.64 grams per cubic meter.

The GOES-10 infrared image at 1830Z depicted a large area of low to middle layer clouds covering most of Arizona with four areas of convective clouds depicted by the enhanced colors. The largest area of convective clouds identified as cumulonimbus clouds was located over the southern portions of the image, located south of Phoenix (KPHX). The second area was over eastern Arizona, east of Winslow (KINW) and north of Show Low (KSOW). The third largest area was associated with a line of towering cumulus and cumulonimbus clouds extending from southern Nevada near Bryce Canyon (KBCE) southwestward to Kingman, Arizona (KIGN), and Bullhead City. The fourth area of convective clouds was identified ahead of this line west of Grand Canyon (KGCN) and immediately south of the accident site. The main centroid of this area of cumulonimbus clouds was located approximately 25 miles south of the accident site at 1830Z, with a radiative temperature showing cloud tops near 36,000 feet. Over the accident site, the radiative temperature corresponded to cloud tops near 27,000 feet.

The GOES-10 visible image for 1830Z on September 8, 2002, depicts an area of towering cumulus clouds over the accident site with a larger area of cumulonimbus clouds to the south of the accident site.

The closest available NWS Weather Surveillance Radar-1988, Doppler (WSR-88D) was located at Cedar City, Utah (KICX), approximately 93 miles northwest of the accident site. The radar beam center was located at approximately 17,465 feet over the accident site, with the base of the beam at 12,730 feet and the top at 22,250 feet. During the period from 1820Z through 1827Z the accident airplane was observed between 19,000 and 21,000 feet, within the 0.6 degree elevation scan.

The FAA Advisory Circular AC 00-24B titled "Thunderstorms" dated January 2, 1983, also defines the echo intensity levels and potential weather phenomena associated with those levels. If the maximum VIP Level are 1 "weak" and 2 "moderate," then light to moderate turbulence is possible with lightning. VIP Level 3 is "strong" and severe turbulence is possible with lightning. VIP Level 4 is "very heavy" and severe turbulence is likely with lightning. VIP Level 5 is "intense" with severe turbulence, lightning, hail likely, and organized surface wind gusts. VIP Level 6 is "extreme" with severe turbulence, lightning, large hail, extensive surface wind gusts and turbulence. These levels are also referenced in the Aeronautical Information Manual (AIM) under the Pilot/Controller Glossary under radar weather echo intensity levels.

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