LAX05LA244

The airplane impacted a road and scrub brush during a forced landing, which was preceded by a total loss of engine power. According to the pilot, he heard a loud "thunk" during takeoff climb and noted a loss of engine power. He manipulated the power lever from the full forward position to the full aft position ("stop-to-stop") and noted he had no power. Post-accident examination of the Pratt & Whitney Canada PT6A -114A engine revealed that the compressor turbine (CT) vane's outer rim liberated a section of metal that damaged the turbine blades downstream. The area of liberated material from the CT vane outer rim was examined by the manufacturer's metallurgists. The fracture surface of the outer rim showed evidence of fatigue with signs of oxidation in some areas indicating the crack had been in existence for some time. The liberated material impact damaged the CT blades and resulted in a loss of power. Review of the operator's records revealed that the engine was approved for an extension beyond the normally recommended 3,600-hour overhaul period, to 5,100 hours. The engine had accumulated 4,461.3 hours at the time of the accident. In addition, the turbine section (hot section) had a recommended overhaul period of 1,800 hours; however, the operator instead elected to utilize an engine trend monitoring program in accordance with a manufacturer issued service bulletin. Many errors were noted with the operator's manually recorded data utilized for the trend monitoring. However, it is not likely that the engine trend data, even had it been correctly recorded and monitored, would have depicted the fatigue cracking in the CT vane outer rim. As a result, the manufacturer issued a service information letter (SIL) PT6A-116 in January 27, 2003 (following a similar investigation), which reminded operators to conduct borescope inspections of the CT vane during routine fuel nozzle maintenance, as the manufacturer's maintenance manual recommended. Review of the maintenance record entries for the accident engine revealed no evidence that a borescope inspection had been conducted in conjunction with the fuel nozzle checks.

History of flight

On July 22, 2005, about 0830 mountain standard time, a Cessna 208B single-engine airplane, N717BT, lost engine power during takeoff climb from the San Carlos Apache Airport (P13) in Globe, Arizona, and impacted the ground east of the airport. The airplane came to rest about 50 yards from highway 70 on the San Carlos Indian Reservation. Baltimore Air Transport (B.A.T.) of Atlanta, Georgia, d.b.a. CorpJet, operated the airplane as a contract cargo flight for United Parcel Service (UPS) under the provisions of 14 CFR Part 135. The airplane sustained substantial damage and the airline transport pilot, sole occupant, sustained minor injuries. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed for the cross-country flight. The flight's intended destination was Safford Regional Airport (SAD), Safford, Arizona.

On the morning of the accident, the pilot flew the airplane from Phoenix to Globe with about 600 pounds of cargo and 1,600 pounds of fuel. The flight lasted approximately 30 minutes and he experienced no problems and noted no anomalies. At Globe, the pilot offloaded about 200 pounds of cargo and departed for Safford. He did not add fuel at Globe.

Departing Globe, the pilot noted the winds were very light, if not calm, and there was a high overcast cloud layer (around 25,000 feet). He took off with a normal takeoff flap setting of 20 degrees, and a takeoff power setting just below normal (which according to the pilot was between 1,800 and 1,900 RPM). During engine start he noted a normal inlet turbine temperature (ITT) and oil pressure indication, but during takeoff, he concentrated on torque setting and didn't notice the ITT and oil pressure during climb out.

The pilot heard a loud "thunk" and noted a loss of engine power. Shortly after the "thunk" he looked at the engine instruments, but could not remember their readings. He noted that three annunciator lights were illuminated ("low oil pressure, low fuel pressure, and low vacuum pressure"). He manipulated the power lever from the full forward position to the full aft position ("stop-to-stop") and noted he had no power. When asked if he performed any of the emergency procedures, he indicated that he did not remember but didn't think so because he was more concerned about finding a suitable landing site. When asked if he tried to feather the propeller he said he did not believe he did because he was focused on flying the airplane.

The pilot could not remember what altitude he was when he heard a loud "thunk" but knew he was high enough to make a turn back toward the departure airport. During the turn, the descent rate was such that he realized he would not be able to make it back to the airport and concentrated on finding a landing area. After realizing he would not make it to the airport, the pilot initially set up to land on highway 70, but believed there was too much traffic and he would hit something. He then focused on landing in a field adjacent to the highway. When asked if he had manipulated the flaps, the pilot said he could not remember. He said he put in 20 degrees of flaps for takeoff, but could not remember if he ever retracted them following takeoff or during the initial climb.

The airplane touched down on the edge of highway 70, bounced down an incline on the side of the road and came to rest upright in the dirt among scrub brush.

Personnel information

The pilot held a second-class medical certificate issued on March 23, 2005, with a limitation indicating that the medical was "not valid for any class after March 31, 2006." He was an airline transport pilot with an airplane multi-engine land (AMEL) rating, and held a commercial pilot certificate with an airplane single-engine land (ASEL) rating. He was also a certificated flight instructor with ASEL, AMEL, and instrument airplane ratings. According to the Pilot/Operator Aircraft Accident Report (NTSB form 6120.1/2) submitted by the pilot, he accumulated a total of 5,545.5 flight hours, of which 203.0 hours were logged in the same make and model as the accident airplane.

The pilot completed his basic indoctrination, aircraft ground, and emergency training on June 25, 2005. On June 26, 2005, the pilot completed a 1.9-hour airman competency/proficiency check ride required by 14 CFR Parts 135.293, 135.297, and 135.299. Review of the company's training record revealed instructors "discussed" abnormal/emergency procedures with the pilot.

Aircraft information

The accident airplane (serial number 208B0863) was manufactured in 2000, and was delivered with the same 675-shaft horsepower Pratt & Whitney Canada (P&WC) PT6A-114A engine that was installed at the time of the accident (serial number PCE-PC0823).

The PT6A-114A engine is positioned in the nose of the Cessna 208 with the inlet to the compressor section oriented toward the aft end of the engine by the accessory section. When looking at the profile view of the engine, the propeller reduction gearbox is oriented toward the front, followed aft by the turbine section, combustion section, compressor section, and ending with the accessory gearbox. The airflow through the engine flows into the inlet and moves forward through the compressor section, before making an "S" turn through the diffuser and turns 180 degrees to enter the combustion chamber. Fuel is introduced, ignited and the expanding hot gas exits the combustion chamber and turns 180 degrees back toward the nose of the airplane where it then enters the turbine section. The hot gas continues through two turbines before exiting the exhaust, which is located toward the front of the engine near the propeller reduction gearbox. The compressor section consists of three axial stage compressors and one centrifugal impeller, which are all driven by the compressor turbine (referred to as the CT or N1). Forward of the compressor turbine is the power turbine (referred to as the PT or N2), which drives the propeller. The two rotating assemblies are not connected and turn at different speeds and in opposite directions, which is referred to as a "free turbine engine."

Review of the B.A.T.'s operations specifications revealed the accident airplane was on an approved airworthiness inspection program (AAIP), which followed the Cessna 208 phasecard inspection program. The engine was to be maintained in accordance with the manufacturer's maintenance manual and P&WC's service bulletin (SB) 1003R25, which allowed the time-in-service interval for overhaul to be extended beyond the normal recommendation of 3,600 hours, and hot section inspections to be conducted on condition. The operations specifications further dictated that the operator must also incorporate the manufacturer's recommended engine trend monitoring program.

Review of the aforementioned SB revealed operators could extend the time-between-overhaul (TBO) by 500-hour intervals on a sampling basis. The operator must have submitted at least one engine from their fleet that has reached its 3,600-hour TBO interval, had it inspected and overhauled, and requested a TBO evaluation report from a P&W Distributor and Designated Overhaul Facility (DDOF). If the sample engine proved to be in a satisfactory condition, P&W would consider recommending a fleet extension to 4,100 hours. In addition, the hot section inspection (HSI) was to be conducted within 50 hours of its normal HSI interval of 1,800 hours, unless it underwent engine condition trend monitoring in accordance with the Engine Condition Trend Monitoring Analytical Guide (EAG) Manual part number (P/N) 3043607.

B.A.T. had undergone 3 separate sampling approvals to reach their approved TBO of 5,100 hours; the last approval was dated July 19, 2001.

According to B.A.T. maintenance personnel, the accident engine had been on P&WC's approved trend monitoring program since its delivery in 2000. Pi