Aviation Accident Summaries

Aviation Accident Summary NYC07LA178

Orlando, FL, USA

Aircraft #1

N724RK

Beech B60

Analysis

The airplane was in visual conditions, on an instrument flight rules flight plan, at flight level 270 (FL270), and in contact with air traffic control (ATC). The pilot reported that he observed a 10-mile wide opening between a large thunderstorm cell, and a smaller cumulonimbus (CB) build-up that was developing just to the southwest of the large cell. As the airplane approached the gap between the two cells, the pilot noticed that the CB was developing faster than he had anticipated, with tops that had grown from about FL270, to about FL290. The airplane's onboard weather radar was depicting only light precipitation, while the large thunderstorm cell northwest of the airplane was depicting extreme precipitation. As the airplane entered the northeast side of the CB, it encountered light to moderate turbulence, which was followed by an extreme downdraft. The pilot initially lost control of the airplane, then recovered at an altitude of about 14,500 feet, and the airplane sustained substantial damage. A reconstruction of the "WARP NEXRAD" weather data displayed to the ATC controller during the time leading up to the airplane's loss of control, revealed that the airplane had entered an area of extreme (VIP 6) echoes. Review of ATC communications revealed that the pilot had been in contact with the ATC controller for about 5 minutes before the airplane's encounter with the adverse weather, and the controller did not provide any weather advisories to the pilot.

Factual Information

On July 26, 2007, about 1820 eastern daylight time, a turbine powered Beech B60, N724RK, was substantially damaged when it encountered weather while in cruise flight near Orlando, Florida. The certificated commercial pilot and two passengers were not injured. Instrument meteorological conditions prevailed, and an instrument flight rules flight plan had been filed for the flight that departed Fort Lauderdale/Hollywood International Airport (FLL), Fort Lauderdale, Florida, destined for Reading, Pennsylvania. The personal flight was conducted under 14 Code of Federal Regulation Part 91. According to the pilot, the flight departed FLL, climbed to flight level 270 (FL270), and intercepted "J20" toward the Orlando Executive Airport (ORL), without incident. Air traffic control (ATC) advised the pilot to deviate to the west around ORL, if necessary, due to weather. Approximately 30 nautical miles from ORL, the pilot requested a direct clearance to the Craig VORTAC, which was denied by ATC. At 10 miles from ORL, the airplane was cruising in visual flight rules (VFR) conditions, when the pilot observed a 10-mile wide opening between a large thunderstorm cell, and a smaller cumulonimbus (CB) build-up that was developing just to the southwest of the large cell. As the airplane approached the gap between the two cells, the pilot noticed that the CB was developing faster than he had anticipated, with tops that had grown from about FL270, to about FL290. The pilot utilized a Bendix/King RDS-82VP onboard weather radar, which was depicting only light precipitation, while the large thunderstorm cell northwest of the airplane was depicting extreme precipitation. The pilot navigated closer to the CB to stay clear of the large thunderstorm cell. As the airplane entered the northeast side of the CB, it encountered light to moderate turbulence, which was followed by an extreme downdraft. The pilot further stated: "...The altimeter began to unwind rapidly and I tried to correct the altitude change with up elevator pressure, as well as additional power. This corrected the situation momentarily, but the downdraft continued and I feared that I would compromise the elevators if I continued to apply the pressure necessary to maintain altitude. I relaxed the pressure and pulled the torque on both engines to idle, to try [to] introduce drag to slow the descent. At this point in time we were losing approximately 4 to 5 thousand feet-a-minute and the aircraft began to roll left. My memory from that moment forward is blurred, but I am certain that the aircraft entered a downward spiral to the left with an attitude greater than 100 degrees left, and a near vertical descent. The artificial horizon (AH) tumbled at that point, I thought that we would not recover. The AH righted itself briefly and tumbled again. The AH righted itself one more time and I reacted immediately with right aileron and rudder and the aircraft rolled level. As it began to roll level, I began to apply up elevator and power in an attempt to arrest the decent. The airspeed began to drop and the aircraft remained level..." The airplane was recovered at an altitude of about 14,500 feet. Shortly thereafter, the airplane exited the clouds. The pilot noticed what appeared to be wrinkles in the upper skin of the left wing. He further noticed that the right elevator outboard hinge was separated from the stabilizer and that both the elevator and stabilizer were damaged. The right elevator was bent downward approximately 30 degrees, about two-thirds from the root. The pilot elected to divert to the Brunswick Golden Isles Airport, Brunswick, Georgia, where the airplane landed without incident. On July 28, 2007, the airplane was examined by a Federal Aviation Administration inspector. According to the inspector, damage to the airplane included, but was not limited to, 14 burn marks that were located at the base of the left wing winglet. The left wing also contained wrinkling on the upper surface, about 1 foot outboard of the engine, forward of the front spar, and 3 feet outboard of the engine, from the forward spar aft 10 inches. The right elevator outboard hinge attach point was broken, and the elevator was bent at the mid-attach point. The right horizontal stabilizer was bent 2 feet from the inboard tip, and the lower skin was concaved from the tip to 2 feet inboard. According to a National Transportation Safety Board Air Traffic Control Specialist's Factual Report, review of radar and voice communications revealed that N724RK contacted the Jacksonville air route traffic control center (ARTCC) about 1815, and reported level at FL270. During the next 4 minutes, the controller handled several other aircraft that were deviating around weather located mainly in the north half of the sector. At 1820:58, the controller noticed N724RK was in a turn to the west and transmitted, "November four romeo kilo I see you're in a left turn there sir...say your intentions." The pilot replied, "...a little off here." The controller asked the pilot to repeat his message, and the pilot stated, "We thought we saw a hole through here and we're just getting back." The controller told the pilot that a right turn to heading 270 would help get around the weather, but there was no response. At 1821:56, the controller again attempted to contact N724RK, and instructed the pilot to turn right to heading 270. The pilot responded at 1822:05, with "OK, we're through it, sorry about that, we thought, we thought we saw a hole, we were just skirt - going through it and it closed up really fast, so, uh...we're back." When asked to confirm his altitude, the pilot replied, "...climbing through eighteen seven now for uh trying to get back up to 270 now...sorry about that." The controller instructed the pilot to maintain FL250, which was acknowledged by the pilot. A reconstruction of the "WARP NEXRAD" weather data displayed to the Jacksonville ARTCC controller's during the time leading up to the airplane's loss of control revealed that the airplane had entered an area of extreme (VIP 6) echoes. The controller did not provide any weather advisories to the pilot prior to the airplane's encounter with the adverse weather. A weather observation taken at ORL, which was located about 3 miles north-northwest of the airplane's position at the time of the encounter, included: winds from 360 degrees at 22 knots; visibility 1 1/2 statue miles in heavy rain; few clouds at 500 feet, overcast ceiling at 5,000 feet; temperature 27 degrees Celsius (C), dew point 23 degrees C; altimeter 30.05 inches of mercury. The pilot reported that he had accumulated approximately 1,580 hours of total flight experience, which included about 275 hours in the same make and model as the accident airplane.

Probable Cause and Findings

The pilot's improper weather evaluation during cruise flight. Contributing to the accident was the air traffic controller's failure to issue in-flight weather avoidance assistance and the convective turbulence.

 

Source: NTSB Aviation Accident Database

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