14 CFR Part 91: General Aviation
Accident occurred Wednesday, June 29, 2011 in Thornton, CO
Probable Cause Approval Date: 03/08/2012
Aircraft: CESSNA R182, registration: N2344C
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
Recorded radar information showed the airplane maneuvering at an altitude of about 500 to 600 feet above ground level and a groundspeed of about 110 knots. Several witnesses saw the airplane’s wings rock before the airplane entered a steep left bank diving turn toward the ground. This occurred about the same time that the wind on the ground began gusting. The airplane impacted the ground inverted, slightly nose-down in a near flat attitude and exploded and a postimpact fire ensued. A postaccident examination of the airplane showed no anomalies indicative of any systems problems prior to the accident. A study of weather conditions in the area at the time of the accident showed a fast moving thunderstorm cell over the area, which was capable of producing severe downdrafts indicative of a microburst. Flight Service Station records showed the pilot did not contact them for any services. Weather forecasts for the time-period the airplane was operating predicted fast moving thunderstorms with high wind gusts and the potential for low level wind shear and microburst conditions.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's inadvertent encounter with a microburst while operating at a low altitude, which resulted in a loss of control from which the pilot could not recover. Contributing to the accident was the pilot’s inadequate preflight planning for the forecasted severe weather conditions.
HISTORY OF FLIGHT
On June 29, 2011, at 1523 mountain daylight time, a Cessna R182, N2344C, impacted an open field in Thornton, Colorado. The commercial pilot, the sole person on board the airplane, was fatally injured. A post impact fire ensued and the airplane was substantially damaged. The airplane was registered to Julair, LLC, doing business as All American Aerials, Incorporated, and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a business flight. Visual meteorological conditions prevailed for the local flight which was being operated without a flight plan. The flight departed Front Range Airport (FTG), Watkins, Colorado, approximately 1425.
The pilot's wife said she spoke with him by telephone just before he took off. She said that the he told her that he was going to go up and "shoot a couple of thousand pictures." She said that he voiced no concerns abbout the weather or how his airplane was performing.
Approach control radar recorded a track depicting a Visual Flight Rules 1200 code at the time and in the area where the airplane would have been. The radar track showed the airplane come out of FTG (elevation 5,516 feet), fly up to the Thornton area, and begin a series of turns. The airplane was operating at an altitude between 5,800 to 6,300 feet mean sea level (msl) and a groundspeed of approximately 110 knots.
A review of radar information for the last 8 minutes of the flight, showed the airplane maneuvering just south of the E-470 toll way 2.23 miles northeast of the accident site at an altitude of 6,000 feet msl. The airplane made several orbits around the area of East 138th Court and Boston Street. At 1516:03, the airplane turned west to a heading of approximately 260 degrees. The airplane continued west at an approximate groundspeed of 112 knots until 1517:58, when the airplane made a left turn to the south. The airplane continued south on an approximate heading of 170 degrees for two and a half minutes until reaching 104th Avenue. The airplane turned northeast on an approximate 045 degree heading and continued northeast until 1521:03. The airplane then turned north and flew just east of Quebec Street at an altitude of 5,500 feet msl and a groundspeed of 94 knots until reaching 123rd Avenue. The airplane then made a left turn to the south. At 1521:54, the airplane disappeared from radar. The airplane’s last recorded altitude was 5,300 feet.
Witnesses said the airplane was maneuvering over the Thornton area at a low altitude at the same time that high wind suddenly occurred on the surface. One witness said he saw the airplane’s wings “dipping” up and down, and the airplane suddenly banked steeply to the left before impacting the ground. Several witnesses said that after the airplane impacted the ground, it exploded and the fire started.
The pilot, age 41, held a commercial pilot certificate with single and multi engine land, instrument airplane ratings. The pilot reported on renewal of his pilot insurance policy on December 6, 2010, a total flying time of 18,000 hours and 8,200 hours in the Cessna 182. The policy renewal indicated the pilot successfully completed a flight review on July 5, 2011. Pilot logbooks were never recovered and were suspected destroyed in the airplane.
The flight instructor who gave the pilot his last flight review said that that the pilot was a step above other pilots that he gave flight reviews to. He said that the day the pilot came to him for his flight review; the pilot told him that this was a checkride for him and he wanted to do everything that was in the Practical Test Standards for a private pilot. The pilot performed departure stalls, traffic pattern stalls, slow flight, turns around a point, and patterns and landings. The flight instructor said the pilot showed good knowledge and although he was not sure, thought he had some professional flight training.
Federal Aviation Administration pilot medical records indicated the pilot completed a class 2 physical in April, 2010.
A few days prior to the accident, the pilot spoke to another pilot that was based at Front Range Airport. The pilot told him that he was taking photographs of residential and commercial real estate from his airplane with a digital camera. The pilot told him that he had business in Colorado and had been in the area for about a week. The pilot told him how he flew the airplane and took photographs out of the pilot window at the same time. The pilot told him he had been doing it for some time and was pretty good at it. The pilot also told him of a time when while he was taking pictures, his airplane struck a guy wire. The pilot told him that it hit the wing just outside of the strut, but he was able to fly his airplane back and land it without incident.
The pilot’s wife spoke to the pilot by cellular telephone approximately 10 minutes before the pilot took off. She said that he was in good spirits and did not indicate that he was concerned with the weather conditions or the airplane’s capabilities. She also said that he was in good health.
The airplane was a 1978 Cessna model R182. Airframe and engine logbooks were not recovered and were suspected destroyed in the airplane.
A review of work orders reflecting maintenance performed by a repair station at the pilot’s home airport in Marshfield, Wisconsin, dating back to May 2008, showed that an annual inspection was performed in April 2010. At the annual inspection, the airframe had 10,091.4 total hours. Minor maintenance was performed on the airplane by the repair station in June, September, and October 2010, and February and March 2011. The last work order, dated March 28, 2011, indicated the repair station cleaned, greased, and cycled the landing gear system and adjusted the rigging on the right nose landing gear door.
At 1534, the aviation routine weather report for Denver International Airport (DEN), 12 nautical miles east-southeast of the accident site was winds 190 at 15 knots gusting to 21 knots, visibility 10 miles, thunderstorm, scattered clouds at 8,000 feet msl, broken ceilings at 13,000 and 20,000 feet msl, temperature 32 degrees Celsius, dew point 1 degree Celsius, altimeter 29.99 inches, remarks; thunderstorm beginning 1532, rain beginning 1516 ending 1525, occasional lightning in the vicinity south, thunderstorm in the vicinity south moving northeast, hourly precipitation amount zero inches.
The closest Terminal Aerodrome Forecast (TAF) reporting location to the accident site was Rocky Mountain Regional Airport (BJC). The TAF obtained for the accident time was issued at 1435 and was valid for a 21-hour period beginning at 1500. The TAF forecast for BJC expected wind from 350 degrees at 9 knots, visibility greater than 6 miles, scattered cumulonimbus clouds at 8,000 feet agl, and a broken ceiling at 15,000 feet. Thunderstorms were expected in the vicinity after 1600, with a temporary variable wind at 20 knots gusting to 35 knots, thunderstorm, and light rain, with a ceiling broken at 8,000 feet in cumulonimbus clouds.
At 1038, the National Weather Service (NWS) Forecast Office in Boulder, Colorado, issued a Hazardous Weather Outlook for central and eastern Colorado, which discussed a better chance for showers and thunderstorms developing during the afternoon with the main threat from these showers and thunderstorms being gusts to 50 miles per hour.
At 1225, the NWS Forecast Office in Boulder, Colorado, issued an Area Forecast Discussion for eastern Colorado, which discussed high based convection expected to develop into the afternoon with gusts to 35 knots likely in and near any showers or thunderstorms. Higher gusts were possible based on dry adiabatic mixing and these stronger gusts could cause landing and takeoff delays.
The Denver Center Weather Service Unit issues a Meteorological Impact Statement, valid at the time of the accident for the Denver Air Route Traffic Control Center (ZDV) area, advised that the low-level wind shear and microburst potential between 1300 and 1800 was moderate to high.
The pilot received takeoff clearance from Front Range tower prior to his departure. He confirmed the clearance and his intent to depart to the north. No further communications occurred between the pilot and any air traffic controlling agency.
A review of Flight Service Station records indicated the pilot did not contact them for any services.
WRECKAGE AND IMPACT INFORMATION
The airplane impacted in a rolling prairie grass field and came to rest inverted next to a horse pen approximately 330 feet northwest of a house. The elevation of the terrain in the area was approximately 4,800 feet msl.
The airplane wreckage path was along a common heading of 090 degrees magnetic. The wreckage encompassed an area defined by an initial impact point extending 112 feet to where the airplane main wreckage came to rest.
The first impact was evidenced by a 30-inch long scrape running parallel to the wreckage path followed by a spray of dirt that extended east for approximately 15 feet. In this area were several white colored paint chips.
A second point of impact was located 43 feet east of the initial impact mark. It consisted of an 18-inch wide, 12 inch deep smooth strike in the ground which produced a hole and dislodged a large piece of dirt that was 2 feet in front of the strike. The east side of the hole was smooth and showed gray paint transfer. At the right end of the smooth side of the hole were two parallel running white stripes which equated to the white strips at the airplane’s propeller blade tips.
In the immediate vicinity of the hole were large pieces of broken clear Plexiglas. The pieces were clean except for some dirt spray. Also in this area was the airplane’s magnetic compass, pieces of the upper engine cowling, broken pieces of the forward windscreen support posts, white colored paint chips, map pages, and personal items.
Approximately five feet left and two feet aft of the hole was the airplane’s right wing tip. It was broken longitudinally along the attachment rivets. The position light had been broken out.
From the second impact point extending east for approximately 39 feet was an area of debris which contained more pieces of clear Plexiglas, pieces of the fuselage, pieces of door post, and pieces of paper. At the end of the debris area was the right window frame. It was broken out of the door. The Plexiglas was gone, and it had sustained charring from the fire. Just east of the window frame was the airplane’s right cabin door. It was broken out at the hinges, was bent aft and buckled outward, and was charred. The door handle was in the closed and locked position and the locking pin was extended.
The airplane main wreckage consisted of the majority of the airplane’s remaining structure. The fuselage remains were oriented on a south-southwesterly heading.
The cowling, cabin, baggage compartment and aft fuselage to just forward of the empennage were consumed by fire. The left wing with exception of the forward spar was consumed by fire. The inboard portion of the right wing to include the fuel tank and flap were consumed by fire. The right wing outboard of the flap to include the right aileron was charred, melted and partially consumed. The main landing gear was charred. The wheels and tires were consumed by fire.
Flight control continuity was confirmed from the aileron actuators to the remains of the mixer bar and control yokes.
The airplane’s empennage was inverted and resting on the top of the vertical stabilizer and the tip of left horizontal stabilizer. The horizontal stabilizers and elevator showed heat damage, partial melting, and paint blistering. The left horizontal stabilizer was bent upward approximately 10 degrees at mid span. The vertical stabilizer and rudder also showed heat damage and paint blistering.
Flight control continuity was confirmed from the elevator and rudder to the remains of the rudder pedals and control yokes.
The airplane engine was resting inverted on the upper cowling forward of the consumed cabin area. The firewall and engine mounts were crushed downward and bent aft. The engine was intact and showed heat damage from fire, especially the aft section where the dual magnetos, oil filter, fuel pump, and vacuum pump were installed. The crankshaft was partially fractured just aft of the flange. The propeller hub was intact. Both propeller blades were broken in their mounts and fractured approximately 10 inches outboard of the hub. The hub and blade remains showed heat damage and partial melting.
A 26-inch long section of propeller blade was located 18 feet south of the main wreckage. It was fractured laterally across the face of the blade, approximately mid span. The fracture was consistent with an overload failure. The blade section, which included the blade tip showed chordwise scratches and paint rubs consistent with a ground contact. The section was bent torsionally and showed several nicks in the leading edge.
The airplane wreckage was recovered and transported to a repair station and salvage facility for further examination.
A post-impact fire ensued at the time the airplane impacted the ground. The fire burned an area that extended west to east along the airplane’s crash path for approximately 70 feet, and north to south for approximately 72 feet. The fire continued until county fire fighters arrived on the scene and extinguished the fire.
MEDICAL AND PATHOLOGICAL INFORMATION
An autopsy was conducted by the Adams County Coroner on June 30, 2011. The Coroner concluded the pilot died from blunt force injuries sustained in the crash.
Results of toxicology testing of samples taken were negative for all tests conducted.
TESTS AND RESEARCH
The airplane engine, systems, and instrumentation were examined at Greeley, Colorado. The engine showed heavy impact and fire damage to the accessories, wiring harness, muffler, and exhaust manifold. The case and cylinders were intact. The accessories were removed and the crankshaft and camshaft was rotated from the accessories case. The crankshaft and camshaft rotated normally. All valves, rockers, and pushrods showed normal movement. Thumb compression was confirmed on all 6 cylinders.
An examination of the flap actuator indicated the flaps were at a position approximating 10 degrees.
The landing gear was retracted. The elevator trim actuator found extended 1.4 inches, a position indicating nose up trim.
Flight and engine instruments were charred, melted, and partially consumed by fire. The fuel selector indicator and valve confirmed that the selector was in the “both” position, indicating both wing tanks were supplying fuel to the fuel pump and carburetor.
The Cessna R182 Pilots Operating Handbook shows the minimum stall speed at a weight of 3,100 pounds, most forward center of gravity, zero degrees of flap deflection, and zero degree bank angle to be 42 knots indicated airspeed. With 20 degrees of flaps extended, the stall speed decreases to 30 knots.
ADAMS COUNTY — The FAA said a commercial pilot who died last year in a field near Thornton was taking “a couple of thousand pictures” of residential properties for business when the plane crashed.
Salil Sinha, 41, of Marshfield, Wisc., was the only person on board. The plane exploded on impact.
The FAA released its findings of fact on the crash of the Cessna R182 earlier this month, but it did not indicate why the plane crashed. Witnesses said the airplane was maneuvering over the Thornton area at a low altitude at the same time that high wind suddenly occurred on the surface. One witness said he saw the airplane’s wings “dipping” up and down, and the airplane suddenly banked steeply to the left before impacting the ground. Several witnesses told the FAA after the airplane impacted the ground, it exploded and the fire started.
The plane took off from Watkins about an hour before the crash. Sinha did not file a flight plan. The pilot’s wife said she spoke with him just before takeoff for about 10 minutes. Sinha told her he was going to go up and “shoot a couple of thousand pictures” but voiced no concerns about the weather or how the plane was performing. Sinha’s wife said her husband “was in good spirits” and “in good health.”
The FAA’s report said a few days prior to the accident, Sinha pilot spoke to another pilot based at Front Range Airport. The pilot told him that he was taking photographs of residential and commercial real estate from his airplane with a digital camera. The pilot told him that he had business in Colorado and had been in the area for about a week. The report went on to say the pilot told him how he flew the airplane and took photographs out of the pilot window at the same time. The pilot told him he had been doing it for some time and was pretty good at it.
The pilot also told him of a time when while he was taking pictures, his airplane struck a guy wire. The pilot told him that it hit the wing just outside of the strut, but he was able to fly his airplane back and land it without incident.
The National Weather Service’s report for Denver International Airport at 3:34 p.m. included southwesterly winds at 15 knots gusting to 21, 10 miles of visibility, a thunderstorm in the area and scattered clouds at 8,000 feet, or about 2,700 feet off the ground. The closest reporting facility to the accident scene was at Rocky Mountain Regional Airport in Jefferson County. Its report was recorded shortly after Sinha took off, and it expected winds from the north at nine knots, visibility greater than six miles, scattered clouds and expected thunderstorms by 4 that afternoon.
The weather service also issued a forecast discussion earlier in the afternoon, about three hours before the crash. It talked about high-based thunderstorms with winds gusting to 35 knots. A meteorological impact statement, valid at the time of the accident, said low-level wind shear and microburst potential between 1 and 6 p.m. that day was “moderate to high."
Sinha flew at an altitude between 5,800 and 6,300 feet (about 600 to 1,100 above the ground), according to the FAA report. The plane’s speed was 110 knots. For the last eight minutes of the flight, Sinha was just south of E-470 at 6,000 feet and made several orbits around 138th Court and Boston Street. He turned west for almost two minutes, then turned south for 2 ½ minutes until he reached 104th Avenue.
At that point, the FAA said the plane turned northeast for almost five minutes before heading north. The FAA said Sinha flew just east of Quebec Street at 5,500 feet until he reached 123rd Avenue. There, he turned to the south and disappeared from radar. The report said Sinha’s last recorded altitude was 5,300 above sea level.
The FAA said Sinha had a commercial pilot certificate license with single- and multi-engine land instrument airplane ratings. He renewed his pilot insurance policy six months before the crash. He had flown for 18,000 hours and 8,200 hours in the Cessna. The FAA said it couldn’t recover pilot logbooks from the airplane. It suspected they were destroyed in the fire.
The flight instructor who gave Sinha his last review told the FAA Sinha was “a step above other pilots,” according to the report.
“He said that the day the pilot came to him for his flight review, the pilot told him that this was a check ride for him and he wanted to do everything that was in the Practical Test Standards for a private pilot,” the report said. “The pilot performed departure stalls, traffic pattern stalls, slow flight, turns around a point, and patterns and landings. The flight instructor said the pilot showed good knowledge and although he was not sure, thought he had some professional flight training.”
The plane’s last work order was in March. It showed the repair station was cleaned and greased. It cycled the landing gear system and adjusted the rigging on the right nose landing gear door.
The report said Sinha’s plane crashed in a field and came to rest next to a horse pen, about 330 feet from a house. The debris field spread out over 112 feet. The first impact showed a 30-inch long scrape to the wreckage, followed by a spray of dirt that extended for 15 feet. A second point of impact was 43 feet east of the first impact point. It consisted of an 18-inch wide by 12-inch deep smooth strike in the ground, the report said. It produced a hole in the ground and dug up a 2-foot piece of dirt. The Adams County coroner said Sinha died from injuries in the crash, not from the fire. Toxicology tests were negative.