ATL03FA068

The flight was in cruise flight at 27,000 feet when the airplane encountered unforecasted severe turbulence. The pilot made a "mayday" on the airplane radio to Jacksonville Center. Within several seconds the airplane accelerated from 175 knots through 300 knots groundspeed and descended from 27,000 feet to 16,500 feet. The airplane disappeared from radar coverage and was located by Sheriff Department personnel 15 miles north of Homerville, Georgia, in a swampy area. Airframe components recovered from the accident site were submitted to the NTSB Materials laboratory for examination. The examinations revealed all failures were due to overload. Examination of the airframe revealed that the airframe design limits were exceeded. The pilot did not obtain a weather briefing before the flight departed.

History of flight

On March 27, 2003, at 0113 eastern standard time, a Rockwell 690B, N53LG, registered to Haulers Insurance Company Inc., operating as a 14 CFR Part 91 positioning flight, broke up in-flight while descending in the vicinity of Homerville, Georgia. Instrument meteorological conditions prevailed at flight altitude and an instrument flight plan was filed. The airplane was destroyed. The airline transport rated pilot and the sole passenger received fatal injuries. The flight originated from Mount Pleasant, Tennessee, after the pilot received an instrument flight rules clearance and departed on March 26, 2003, at 2300 central standard time.

Communication with Air Traffic Control Facilities along the route of flight before initial contact with Jacksonville Air Route Traffic Control Center (ARTCC) were normal. A review of radio communications between Jacksonville ARTCC and the pilot revealed the pilot had contacted Jacksonville ARTCC at 00:53:26. The pilot stated, "good evening Jacksonville commander five three lima golf with you at flight level two seven zero." At 01:12:10, a pilot stated, "mayday mayday." There was no other known recorded communications with the crew of N53LG.

A review of radar and performance data revealed that the airplane was at 27,000 feet mean sea level (MSL), at 175 knots groundspeed, and heading southeast at 01:11:41. At 01:11:55, the airplane was at 26,600 feet in a left turn at 200 knots. At 01:11:57, the airplane was at 25,700 feet at 200 knots. At 01:12:04, the airplane was heading northeast at 23,200 feet at 245 knots. At 01:12:10, the airspeed was 275 knots. The last radar return was at 01:12:16, and the airplane was at 16,500 feet at 299 knots. The airplane was located by Sheriff Department personnel at 0615.

Personnel information

A review of information on file with the FAA Airman's Certification Division, Oklahoma City, Oklahoma, revealed the pilot was issued an airline transport pilot certificate and flight instructor certificate on December 11, 2001, with ratings for airplane single engine land, multiengine land and instrument airplane. The pilot held a second-class medical certificate issued on October 14, 2002, with no restrictions. A review of the pilot's logbook revealed the last recorded entry was on February 21, 2003. The pilot had logged 3,569.4 hours of which 35.6 were in the Rockwell 690B. The pilot's first recorded flight in the Rockwell 690B was on October 21, 2002. A review of documents obtained from the registered owner of the airplane revealed the pilot had flown an additional 10.2 hours between March 7, 2003, and March 23, 2003.

The pilot filed a computer direct user access terminal service (DUATS) instrument flight plan from Mount Pleasant, Tennessee, to Titusville, Florida. The pilot listed himself as pilot, checked NOTAMS, and terminated the DUATS briefing at 12:39:53. The pilot filed a second computer flight plan from Titusville to Mount Pleasant. The pilot listed himself as the PIC, checked NOTAMS, and terminated the DUATS briefing at 12:41:24. No enroute weather information was requested during the DUAT sessions.

Aircraft information

The Model 690B is a high wing, all metal twin-engine pressurized aircraft and is designed primarily for executive transportation. The aircraft environmental system consists of the cabin pressurization and air conditioning system and includes provisions for ram air ventilation during unpressurized flight. The overall environmental system is designed to provide desired passenger and crew comfort during all phases of aircraft operation.

A review of information on file with the FAA Aircraft Records Division, Oklahoma City, Oklahoma, revealed the airplane had no recorded accident or incident history. Both engines had been removed from the airplane on December 4, 2001. According to the engine logbooks, the left engine was overhauled and reconfigured to a TPE-331-10T-516K, with 5,000-hours of time remaining before overhaul on March 8, 2002. The right engine was overhauled and reconfigured to a TPE-331-10T-516K, with 5,000-hours of time remaining before overhaul on March 11, 2002. The left and right engines were reinstalled on the airplane and the last recorded periodic inspection was conducted on April 4, 2002, at Hobbs time 1846.3.The aircraft total time at installation was 6168.3. The pitot system check and transponder inspection was conducted on April 4, 2002. The last recorded logbook entry was on February 21, 2003, at Hobbs time 1,983.4. According to the registered owner the airplane had flown 10.2 hours since February 21, 2003.

A review of refueling records revealed the airplane was last refueled on March 26, 2003, with 250 gallons of Jet A fuel.

Meteorological information

The Surface Analysis Chart for 0100 depicted a low-pressure area in the Gulf of Mexico south of Louisiana with a frontal wave. A stationary front was depicted extending northeast from the low front across the Florida panhandle into southeast Alabama, into central Georgia, before turning into a cold front across South Carolina, North Carolina, and off the Atlantic Coast. A cold front extended to the south of the low-pressure system with a trough of low pressure to the east, which extended into northern Florida. Ahead of the cold front and south of the stationary front a squall line was depicted in the Gulf of Mexico off the Florida west Coast. The accident site was located south of the stationary front and downstream of the low-pressure system.

The Constant pressure charts for 1900 on March 26, 2003, depicted two defined jet streams with wind in excess of 50 knots north and south of the accident site, with the accident site in the confluence region between the two systems. The subtropical jet stream was depicted over central Florida to the south of the accident site with indicated winds of 125 knots at 30,000 feet, which resulted in an approximately 60 knots per 150 mile horizontal wind shear from the accident site to the maximum wind across central Florida.

FAA Advisory Circular 00-45 identifies the potential for moderate turbulence when horizontal wind shears exceed 18 knots per 150 miles, and vertical shears exceed 6 knots per 1,000 feet. Severe turbulence is possible where horizontal shears exceed 40 knots per 150 miles, and vertical shears exceed 10 knots per 1,000 feet.

The Upper Air Data sounding for Jacksonville, Florida, at 1900 on March 26, 2003, at 27,000 feet, showed an isothermal layer or a shallow layer where no temperature occurred. Winds increased rapidly above 30,000 feet with several layers with vertical wind shears greater than 5 knots per 1,000 feet, which are associated with severe turbulence. At 31,000 feet there was a 100 percent probability of severe turbulence. The 1900 Upper Air Sounding for Jacksonville shows at 24,100 feet a 100 percent probability of severe turbulence.

The Satellite Data imagery surrounding the time of the accident depicted a large area of high "cirrostratus" type cloud cover that was indicated by enhanced colors over eastern Georgia, and northern Florida, which extended over the accident site. The cloud band had a defined edge located approximately 30 miles west and northwest of the accident site which corresponded to cloud tops near 33, 000 feet.

The nearest weather reporting facility at the time of the accident was Moody Air Force Base, Valdosta, Georgia, located 15 miles west-southwest of the accident site. The 0056 surface weather observation was: wind 010 at 2 knots, visibility 8 miles in mist, 7,500 scattered, 15,000 broken, 25,000 overcast, temperature 64 degrees Fahrenheit, dew point temperature 59 degrees Fahrenheit, and altimeter 29.87.

There were no pilot reports (PIREPs) recorded over Georgia between 1900 to 0700 in the FAA database. After 0900 there were several reports of light to moderate turbulence reported between 33,000 to 35,000 feet, and one isolated report of