Aviation Accident Summaries

Aviation Accident Summary WPR10LA128

Dolan Springs, AZ, USA

Aircraft #1

N1060X

PIPER AIRCRAFT INC PA-32R-301T

Analysis

The pilot/owner reported that about 30 minutes into the flight, he began to smell fuel. A short time later, the smell became stronger and was accompanied by a sensation of deceleration with no corresponding engine roughness. He immediately initiated an emergency descent and landed in a dry lake bed. During the landing flare, smoke began to stream from the front of the airplane, and after landing the fuselage was consumed by fire. Examination of the fuel inlet line which connects the fuel servo to the fuel flow divider revealed that it was approximately 1 1/2 turns loose at the 'B' nut fitting at the fuel flow divider. Fueling records indicated that at minimum, the airplane had flown 25 to 40 hours since the annual inspection, which was completed 5 months prior to the accident. The mechanic who performed the annual inspection specifically recalled verifying that the 'B' nut fitting was secure. The pilot reported that prior to the annual inspection the airplane had not been producing full power at takeoff. According to the pilot the deficiency was not resolved during the inspection, or on subsequent return trips to the maintenance facility. The pilot continued to fly the airplane with the discrepancy.

Factual Information

HISTORY OF FLIGHT On February 4, 2010, about 1500 mountain standard time, a Piper PA-32R-301T, N1060X, experienced an in-flight fire and force landed in a dry lake bed near Dolan Springs, Arizona. The pilot was operating the airplane under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The certificated commercial pilot/owner and passenger were not injured. The airplane was substantially damaged by fire. The cross-country personal flight departed Saint George Municipal Airport, Saint George, Utah, about 1430, with a planned destination of Kingman Airport, Kingman, Arizona. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated that about 30 minutes into the flight, at an altitude of about 9,500 feet mean sea level, he became aware of the smell of fuel. A few seconds later the smell became stronger and was accompanied by a sensation of deceleration with no reported the engine roughness. The pilot immediately retarded the throttle, and initiated a descent with the intention of making a forced landing. As the pilot flared the airplane for landing, black smoke began to stream from the front of the airplane. During the landing rollout he shut off the master switch, and pulled the fuel mixture aft. After landing, the pilot and passenger immediately exited the airplane and relocated to a vantage point about 2 miles away where they were able to get cell phone reception coverage. For the next 2 hours they watched as the airplane continued to billow smoke, and eventually catch fire. AIRCRAFT INFORMATION The low-wing, retractable-gear airplane, serial number 3257466 was manufactured in 2007, and equipped with a six-cylinder turbocharged Lycoming TIO-540-AH1A engine. Maintenance Records The airplane's Hobbs hour meter, engine tachometer, and maintenance records were consumed in the post-accident fire. The airplane was maintained by the Atlantic Aviation/Pro-Air Aviation maintenance facility in Casper, Wyoming. A copy of an aircraft logbook entry obtained from Atlantic indicated that an annual inspection had been performed on September 10, 2009, at a total airframe time of 319.2 hours. Fueling records obtained from Atlantic indicated that between October 15, 2009, and January 15, 2010, the airplane had been fueled with 493.8 gallons of aviation gasoline. According to the Pilot Operating Handbook, applicable to the airplane type, the fuel burn at various cruise altitudes, temperatures, and power settings varies between 12.5 and 20 gallons per hour. Based on these values, the airplane had been flown at minimum for about 25 to 40 hours after the annual inspection. The pilot/owner reported that prior to the annual inspection the airplane was unable to produce what he considered maximum takeoff power. He believed that the problem was caused by stretched engine control cables, and as such brought this to the attention of Atlantic. The pilot stated that the problem persisted after the annual inspection and he returned the airplane for continued troubleshooting. He reported that the discrepancy was not resolved at the time of the accident flight. The general manager for Atlantic recalled that the airplane had been returned to the facility after the annual inspection, that the travel for the engine control cables were rechecked with no anomalies noted, and the airplane was returned to service. TESTS AND RESEARCH Airframe The airplane was removed from the accident site and examined by the NTSB investigator-in-charge and representatives from Piper Aircraft, Inc., and Lycoming Engines. The fuselage from the firewall aft to the empennage was consumed by fire. Both wings were largely intact, sustained thermal damage inboard of the landing gear, and had become detached from the remaining fuselage. The fuel selector valve was thermally damaged, and its associated fuel lines were destroyed by fire. The Piper representative was able to verify that the fuel selector valve lever was in the OFF position. Engine The engine compartment forward of the firewall was coated in black soot. All of the engines' ancillary components sustained thermal damage. The fuel pump pressure regulator housing and the fuel flow transducer were consumed by fire. All fuel and oil lines were noted to be charred, intact, and still securely attached at their respective fittings. The engine controls were attached at their respective control arms. The turbocharger and associated components were intact. The fuel flow divider-to-fuel injector lines were intact and secure. Examination of the fuel inlet line which connects the fuel servo to the fuel flow divider revealed that it was approximately 1 1/2 turns loose at the 'B' nut fitting at the fuel flow divider. According to the Lycoming representative, the nut fitting on the line was made of stainless steel, with the associated fitting at the flow divider inlet made of steel. Removal of the 'B' nut revealed that its threads were intact and undamaged. ADDITIONAL INFORMATION The engine was subject to an Airworthiness Directive (AD) number 2008-14-07. The aircraft log entry for the last annual inspection noted that this AD was complied with; the mechanic who performed the inspection also stated that in addition to the AD he also used a wrench to confirm the tightness of the fuel inlet line 'B' nut at the fuel flow divider. Examination of the maintenance records did not reveal any history of work that would have required removing the fuel flow divider or its associated inlet line.

Probable Cause and Findings

The fuel flow divider inlet line nut coming loose during cruise flight, resulting in a fuel leak and in-flight fire. The root cause of the loose B-nut fitting could not be determined. Contributing to the accident was the pilot's decision to fly the airplane with a known deficiency.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports