Aviation Accident Summaries

Aviation Accident Summary LAX04FA096

Grass Valley, CA, USA

Aircraft #1

N99LR

Cessna 172K

Analysis

The airplane collided with trees while attempting to land in IFR conditions of near zero visibility in fog. While en route to the destination airport on an IFR clearance, the TRACON controller observed the airplane's transponder discrete code change to 7600 (used by flight crews to indicate a communications failure). The TRACON controller determined that the pilot could hear them, but they could not hear his transmissions. Because of the requirement for full communications in controlled, Class B airspace, they suggested the pilot contact a nearby airport outside of the Class B airspace on the frequency they provided. The pilot contacted the suggested ATCT while 12 miles west of that airport, and the controller could barely hear the pilot's transmissions. The pilot advised the tower to cancel his IFR flight plan and he would proceed visual flight rules (VFR) back to his departure airport without VFR flight following. This was the last communication from the pilot. Witnesses heard the pilot make two approach attempts to land at original departure airport but they could not see the airplane because the airport had become zero visibility and zero ceiling in fog about 20 minutes prior to the airplanes arrival.

Factual Information

HISTORY OF FLIGHT On January 19, 2004, about 1825 Pacific standard time, a Cessna 172K, N99LR, collided with trees while attempting to land at Nevada County Air Park (O17), Grass Valley, California. The pilot was operating the airplane under the provisions of 14 CFR Part 91. The private pilot and one passenger sustained fatal injuries; the airplane was destroyed. Instrument meteorological conditions prevailed, and an instrument flight rules (IFR) plan had been filed but subsequently canceled. The flight originated at O17 at 1648, and was destined for Palo Alto, California. Prior to departure from Grass Valley, the pilot obtained a preflight weather briefing at 1600, and was advised of marginal visual flight conditions. While en route to Palo Alto, the pilot was under the control of Bay Terminal Radar Approach Control (TRACON). Nearing the destination, Bay TRACON observed the airplane's transponder discrete code change to 7600 (used by flight crews to indicate a communications failure). Bay TRACON determined that the pilot could hear them, but they could not hear his transmissions to them. Because of the requirement for full communications in controlled, Class B airspace, they suggested the pilot contact Stockton Airport control tower on the frequency they provided. The pilot contacted Stockton while 12 miles west of the airport, and Stockton could barely hear the pilot's transmissions. The pilot advised Stockton to cancel his IFR flight plan at 1731, and he would proceed visual flight rules (VFR) back to Grass Valley airport without VFR flight following. This was the last communication from the pilot. Witnesses observed/heard the pilot make two approach attempts to land at Grass Valley. According to airport personnel, the airport had been zero visibility and zero ceiling in fog for the 20 minutes prior to his arrival. PERSONNEL INFORMATION At the certificated private pilot's most recent second-class flight physical on June 25, 2002, he reported a total flight time of 1,020 hours with 12 hours in the past 6 months. The pilot also held an instrument rating for airplanes. AIRCRAFT INFORMATION The most recent documented annual inspection occurred on February 20, 2003, at 4,937 recording tachometer hours. The Narco ELT-10 crash locator beacon battery expiration date was noted to expire on August 2003, and was supported by an entry at the annual inspection. The seat belts were dated 1970, with advanced fraying and general deterioration noted. No compliance with the requirements of FAR 91.411, altimeter system and altitude reporting equipment tests and inspection, nor FAR 91.413, ATC transponder tests and inspections were found. The accident site recording tachometer indicated 5,049.16 hours. METEOROLOGICAL INFORMATION The pilot did obtain a standard preflight weather briefing for the planned route of flight. Marginal visual flight conditions existed for the entire route of flight with an AIRMET for instrument flight rules/conditions over the central valley and extending over into the bay area. A moist and stable high pressure airmass existed over the area. Pilot reports indicated that the weather was deteriorating in low level ground fog conditions. WRECKAGE AND IMPACT INFORMATION The accident location was calculated about 0.34 nautical miles south of the Nevada County Airport. The accident site elevation was estimated 2,838 feet mean sea level (msl). Runway 07 elevation was noted on an airport layout plan to be 3,068 feet msl; runway 25 elevation wais noted to be 3,152 feet msl. The area around the airport consists of rolling hills and canyons of the Sierra Nevada foothills. The wreckage path was 190 degrees magnetic with a debris path about 300 feet in length into undulating terrain. The airplane direction gyro was indicating 220 degrees. The airplane's destroyed altimeter was found set to 30.12 inches of mercury in the altimeter adjustable pressure window. A navigational omni bearing selector was set about 187 degrees with a navigation receiver tuned to 115.05. A second nav receiver also noted as nav 1, was between 114/115.20. An automatic direction finder (ADF) receiver was tuned to 910, with the adjustable card at 10 degrees. MEDICAL AND PATHOLOGICAL INFORMATION On January 20, 2004, the Nevada County medical examiner performed an autopsy on the pilot. During the course of the procedure samples were obtained for toxicological analysis by the Federal Aviation Administration (FAA) Civil Aeromedical Institute, Oklahoma City, Oklahoma. The results of the analysis were negative for carbon monoxide, cyanide, and ethanol. The drug analysis was positive for 0.028 (ug/ml, ug/g) AMITRIPTYLINE detected in blood and in liver, and 0.029 (ug/ml, ug/g) NORTRIPTYLINE in blood and liver. A review of the pilot's medical file failed to locate any FAA waiver for the use of an unapproved drug and the requirements of 14 CFR Parts 61, 63, and 65 (operation during medical deficiency). ADDITIONAL INFORMATION The North County airport operator stated that the pilot did not purchase fuel while at Grass Valley. The last refueling information obtained, was at Palo Alto on January 12, 2004, for 21.1 gallons of 100LL. The airplane was on an automatic refueling service provided by the operator to the airplane's designated tie down spot E18. The wreckage was released to the insurance company representative on July 6, 2005.

Probable Cause and Findings

the pilot's continued visual flight into instrument meteorological conditions and failure to maintain an adequate terrain/object clearance altitude. Also causal was the pilot's improper in-flight decision to return to the origin airport in the face of deteriorating weather conditions instead of diverting to a more suitable alternate.

 

Source: NTSB Aviation Accident Database

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