N233GWCessna 172S · 2002

On June 12, 2008, at 1700 mountain daylight time, a Cessna 172S, N233GW, sustained substantial damage when the airplane impacted terrain shortly after takeoff at Beaver Municipal Airport (U52; elevation 5,863 feet), Beaver, Utah. The commercial pilot and one passenger received minor injuries, and a second passenger was seriously injured. Leading Edge Aviation, Ogden, Utah, was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the cross-country flight, which was originating at the time of the accident. A flight plan had not been filed.

A local law enforcement officer, who was one of the first responders to the scene of the accident, reported that the pilot said he took off "going south, up hill. [The airplane] got airborne. The field was coming at him. As he pulled back on the stick, he pulled the airplane into a stall. The engine stalled and the plane fell nose first back to the ground."

In his National Transportation Safety Board (NTSB) Pilot/Operator Aircraft Accident/Incident Report dated June 20, 2008, the pilot reported that the initial departure for the day was from Ogden, Utah, approximately 1100. The flight to Beaver was uneventful and they landed about 1300. He fueled the airplane "so it had 28 gallons on board" in preparation for their return trip later that afternoon. Approximately 1630, the pilot returned to the airport and prepared the aircraft for departure. He listened to the local Automated Surface Observing System (ASOS) and observed the windsock to determine weather conditions. While he was preflighting the airplane, a Beechcraft King Air Life Flight landed on runway 13. The pilot stated, "All three of these wind aids gave indication to a southern departure."

According to the pilot, he taxied for runway 13 and departed using "a short field takeoff technique with zero flaps." Immediately after takeoff the flight encountered wind gusts and wind shear conditions. The engine momentarily lost performance and momentarily sputtered. He checked the mixture control to make sure it was full rich and the throttle was in. Additionally, he had to maneuver the airplane to avoid power lines and a circular agricultural irrigation system. The pilot said he "never noticed any stall buffet, sloppiness in flight control, stall horn or stall itself." The airplane "sank quickly" and he nosed the airplane over to avoid a stall situation; the next thing he recalled was being "nose down in the dirt."

The 23-year-old pilot's most recent first-class Federal Aviation Administration (FAA) medical certificate was issued on January 16, 2008. He held a commercial pilot certificate with single and multiengine land airplane ratings, and an instrument airplane rating. He was a flight instructor in single and multiengine land airplanes, and in instrument airplane. The pilot reported on his NTSB Pilot/Operator Aircraft Accident/Incident Report that he had a total of 231 hours of flight experience in all aircraft, with 175 hours as pilot-in-command. Approximately 100 hours had been accumulated in single engine aircraft, of which 17 hours were in the make and model airplane involved in the accident. The pilot successfully completed his check ride for his flight instructor certificate in single engine airplanes on May 25, 2008.

The operator reported that the pilot received a checkout in the airplane the day before the accident from one of his flight instructors. The flight instructor stated that as part of the checkout, he asked the pilot to perform some weight and balance calculations for his planned flight to Beaver the next day. The pilot had originally planned to take three passengers to Beaver, but after working the calculations, he decided to take only two passengers.

The airplane was a single engine, propeller-driven, four seat airplane, with dual flight controls, which was manufactured by Cessna Aircraft Company in 2002. It was powered by a Lycoming IO-360-L2A reciprocating, direct drive, air-cooled, fuel injected engine, which had a maximum takeoff rating of 180-horsepower (hp).

The airplane was equipped with two wet wing fuel tanks. Each tank held 28 gallons of fuel, with 26.5 gallons usable. The airplane's maximum takeoff gross weight was 2,550 pounds, and its empty weight was 1,717 pounds. The flight instructor provided weights for the pilot and passengers from the previous day's calculations. Using the pilot's estimated fuel on board of 28 gallons, the airplane's takeoff weight was calculated at 2,486 pounds. Using the estimated fuel drained from the airplane of 44 gallons (less 3 gallons of unusable fuel), the airplane's takeoff weight was calculated at 2,564 pounds.

The airplane manufacturer's Pilot Operating Handbook (POH) states: Prior to takeoff from fields above 3,000 feet elevation, the mixture should be leaned to give maximum rpm in a full throttle, static runup. Additionally, in the engine manufacturer's published Operator's Manual, a table for engine performance shows that when properly leaned for a density altitude of 7,457 feet, the normally aspirated engine's maximum output of 180 hp would be reduced to 138 hp.

The airplane manufacturer's POH, in the normal procedures section, states: SHORT FIELD TAKEOFF

A. Wing Flaps----------10 degrees

B. Brakes---------------APPLY

C. Throttle-------------FULL OPEN

D. Mixture--------------RICH (above 3000 feet, LEAN to obtain maximum RPM)

E. Brakes---------------RELEASE

F. Elevator Control----SLIGHTLY TAIL LOW

G. Climb Speed---------56 KIAS (until all obstacles are cleared)

At 1652, the weather conditions at Milford Municipal Airport (MLF; elevation 5,039 feet), Milford, Utah, located 290 degrees and 19 nautical miles (nm) from the accident site, were as follows: wind from 020 degrees at 11 knots, gusting to 16 knots; clear of clouds; temperature 72 degrees Fahrenheit; dew point 14 degrees Fahrenheit; altimeter setting 30.14 inches of Mercury. The density altitude was calculated to be 6,851 feet.

Beaver Municipal Airport's ASOS has weather data storage capability. At 1700, the weather conditions at Beaver Municipal Airport were as follow: wind from 330 degrees at 8 knots, gusting to 14 knots; visibility 10 nautical miles; clear of clouds; temperature 66 degrees Fahrenheit; dew point 23 degrees Fahrenheit; altimeter setting 30.20 inches of Mercury. The density altitude was calculated to be 7,457 feet.

The wind was variable during the pilot's preflight preparation and departure:

1640---340 degrees at 5 knots

1645---360 degrees at 7 knots

1650---350 degrees at 11 knots

1655---360 degrees at 11 knots, gusting to 14 knots

1700---330 degrees at 8 knots, gusting to 14 knots

1705---360 degrees at 12 knots, gusting to 19 knots

1710---310 degrees at 12 knots, gusting to 19 knots

1715---300 degrees at 9 knots, gusting to 19 knots

1720---030 degrees at 3 knots

An FAA inspector interviewed the pilot of the King Air that arrived during the accident pilot's preflight inspection. The King Air pilot reported that at the time he landed (approximately 1643), the winds were variable between 330 to 350 degrees at 5 to 10 knots. He further reported that the sky conditions were clear and he observed no wind shear or hazardous conditions around the airport.

Beaver Municipal Airport is a non-towered airport that uses a Common Traffic Advisory Frequency (CTAF) of 122.9 Mhz for pilots to communicate and announce their intentions. The airport has one paved runway, runway 13/31, which is 4,984 feet long and 75 feet wide; runway 13 has an uphill gradient of 1.5 percent. The terrain surrounding the airport is flat agricultural land, which gently rises to the south (at approximately 150 feet per nautical mile). There is an ASOS weather station on the field and pilots can retrieve current conditions on frequency 119.925 Mhz. The airport is equipped with a segmented circle windsock indicator located approximately 975 feet from the transient parking area and approximately 875 feet from where the taxiway joins the runway.

The airplane came to rest in an alfalfa field approximately 2,850 feet from the end of runway 13, and approximately 1,000 feet to the right of the runway centerline. An FAA inspector estimated the ground scar to be approximately 100 feet in length on a course of 180 degrees. The nose landing gear and the engine were separated from the airplane. The outboard sections of the right and left wings were bent upward, the left wing's rear spar was separated, and the bottom of the fuselage was crushed upwards.

The operator sent personnel to the accident scene to retrieve the airplane. The mechanic who removed the wings for transport reported that he filled four to five 5-gallon containers with fuel from each wing; he estimated that he removed a total of between 44 to 48 gallons of fuel from the wings.

Representatives of the engine manufacturer and the airframe manufacturer performed an examination of the wreckage under the supervision of an FAA inspector, on June 19, 2008, at Logan, Utah. The engine's fuel control unit was examined and tested in Marysville, Washington, on July 24, 2008, under the supervision of a Safety Board investigator. These examinations revealed no preexisting anomalies that would have precluded normal operation of the airplane or its engine.

In a telephone interview with the Safety Board investigator-in-charge, the pilot reported that he used a dipstick to determine the amount of fuel on board the airplane. The airframe manufacturer stated that they do not manufacture or sell dipsticks for the airplane. The manufacturer further stated that there is wing rib structure in the wet wing fuel tank and inaccurate readings are possible. Manufacturer safety personnel estimated that if a pilot used the dipstick method to determine the amount of fuel in a tank, and it rested on the rib instead of the bottom of the tank, there could be 2 to 3 gallons more fuel in the tank than the dipstick reading.