N68718Cessna 340A · 1982

On October 25, 2010, about 0745 Pacific daylight time, a Cessna 340A, N68718, experienced an in-flight loss of control followed by an uncontrolled descent into mountainous terrain about 9 nautical miles (nm) northeast of Morton, Washington. The airplane was substantially damaged. The airline transport certified pilot and two passengers sustained fatal injuries during the business flight. The airplane was owned and operated by Pacific Cataract and Laser Institute (PCLI), Chehalis, Washington. Instrument meteorological conditions prevailed for the cross-country flight, which was conducted in accordance with 14 Code of Federal Regulations (CFR) Part 91, and an instrument flight rules (IFR) flight plan was filed. The flight, which originated from the Chehalis-Centralia Airport (CLS), Chehalis, Washington about 0725, was destined for the Lewiston-Nez Perce County Airport (LWS), Lewiston, Idaho.

The operator's chief pilot reported to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) that the PCLI flight was performed for the purpose of transporting two company employees to one of their business offices. Prior to the flight the chief pilot had received no information indicating any anomalies in the operation of the accident airplane’s systems, including engine assemblies and attitude reference instruments.

The accident pilot received an instrument flight rules (IFR) clearance as filed with the Federal Aviation Administration (FAA). FAA recorded radar track data and communications between the Seattle Air Route Traffic Control Center (ARTCC) and the accident pilot were initially routine. The radar track revealed that the pilot proceeded in an easterly direction toward LWS, the destination airport.

Review of Air Traffic Control communications and radar data revealed that at 07:30:59, the accident airplane was 12 nm east of CLS and climbing about 1,057 feet per minute (fpm) on an easterly course direct to the destination airport, LWS. At 07:38:43, the flight reached 14,800 feet mean sea level (msl), and about this time the pilot requested a higher altitude to 17,000 feet msl. At 07:39:03, the pilot transmitted, “…heading back to Chehalis, “ and at 07:39:10, the pilot stated, “Yah, we’ve lost an engine here so we’re headed back to Chehalis.” At 07:40:03, the transcript revealed that the pilot stated, “We’re losing it.” This was the last transmission received from the pilot. Radar contact with the airplane was lost while continuing its clockwise descending turn.

A further review of the radar data indicated that the airplane was at 14,800 feet msl when it began a right turn of 360 degrees at 8 degrees per second. At 07:39:20, the airplane began a descent, which averaged 5,783 fpm to the last recorded radar return, which was at an altitude of 10,700 feet msl. The airplane continued in the descending right turn until radar contact was lost.

Several employees of a logging company, who were located in a forest about 8 miles northeast of Morton, subsequently reported to authorities that they had heard the sound of a descending airplane. The sound was loud enough to be heard over the noise of their operating equipment. The workers recalled that, at the time, a light rain was falling, low clouds were present, and it was not particularly windy.

After the logging company employees learned that an airplane had, in fact, crashed and were informed of its approximation location, they informed the Safety Board investigator that they believe their location had been between 1/4 and 1/2 mile from the crash site.

The Safety Board's on scene examination of the accident site and airplane wreckage revealed fragmented portions of the cockpit and engine components in a 5-foot-deep impact crater. Several hundred components were also found scattered over the 20 to 30-degree downsloping forested terrain within the 160-foot-long debris field. The debris field fanned out over a 45-degree arc from the main impact area.

The accident site was located in a densely forested area about 36 nm east of the departure airport, at an elevation of 2,940 feet msl. All major structural components of the airframe and most engine components were located in the vicinity of the main wreckage. No evidence of fire was observed. Pertinent portions of the engines, turbochargers, propeller assemblies and airplane systems were recovered to a secured location for further examination.

The pilot, age 70, held an airline transport pilot certificate, with ratings for airplane multiengine land, commercial privileges for airplane single-engine land, and a flight instructor certificate, with ratings for airplane single-engine and instrument airplane. The pilot’s most recent FAA second-class airman medical certificate was issued on June 25, 2010, with the limitation “must wear lenses for distant vision and possess glasses for near vision.”

A review of excerpts from the pilot’s personal logbook and data provided by the company chief pilot revealed that the accident pilot had accumulated 5,493 total flight hours, of which 1,525 were in the Cessna 340A; 1,520 hours were as pilot in command. The data also indicated that within the last 30, 60 and 90 days respectively, the accident pilot had flown 8, 20, and 26 hours in the accident airplane. The pilot’s most recent flight review was successfully completed on November 12, 2009 in the accident airplane.

The 1982-model Cessna 340A, serial number 340A1527, was a twin-engine, low wing, retractable landing gear, pressurized, semimonocoque construction airplane. The airplane was powered by two six-cylinder, air-cooled, horizontally opposed, Continental TSIO-520-NB-2 (serial numbers 276993-R [right position] and 276932-R [left position) engines, rated at 335 horsepower. Both engines had accumulated 3,071.7 hours since new, and 1,557.3 hours since their most recent major overhaul.

A review of aircraft maintenance records revealed that the most recent annual inspection was completed on March 3, 2010, at a total airframe time of 6,051.2 hours; the total airframe time at the time of the accident was 6,107.5 hours.

On August 11, 1999, the airworthiness certificate was changed from Standard to Experimental (for research and development). On September 9, 1999, the airworthiness certificate was changed back to Standard from Experimental.

A further review of the maintenance records indicated the replacement of the right engine fuel pressure regulator, which was in response to a squawk from the accident pilot on September 1, 2010, for the engine being slow to achieve full power. The logbook entry on September 24, 2010, revealed that the fuel pressure regulator was replaced and adjusted per Teledyne Continental Motors (TCM) specifications. According to a FAA inspector, the regulator was adjusted per RAM Aircraft specifications after the mechanics had conferred with TCM and RAM engineers. The airplane was then flown 7.1 hours after the logbook entry and before the accident flight without further anomalies being noted.

The pilot requested a standard weather briefing from the Prescott, Arizona Flight Service Station. The briefing covered a period of about 7 minutes, from 0614:43 to 0621:35.

The weather briefer advised the pilot that stormy weather would continue to affect western Washington for the next couple of days and that snow was falling in the Cascade Mountains above 4,000 feet, as well as gusty winds. The briefer continued by noting that Convective Sigmets were a possibility throughout western Washington, but they haven’t been issued yet. Additionally, moderate to heavy returns were possible throughout the Cascade area westward.

Airmet Sierra was valid for mountain obscuration, with mountains obscured by clouds, precipitation and mist throughout the rest of the day. Also, Airmet Tango was in effect for moderate turbulence below flight level (FL) 180, and Airmet Zulu was valid or moderate icing between the freezing level and 15,000 feet, with freezing level as low as the surface up to about 6,000 feet.

The weather briefer then advised the pilot that the current Chehalis automated weather report has surface winds out of the south-southeast 160 degrees at 10 knots, gusts to 17, visibility 5 miles and light rain, scattered clouds at 2,700 feet, broken clouds at 3,400 feet, overcast clouds 4,500 feet, temperature 9 degrees Celsius (C), dew point 8 degrees C, and that “.. the radar screen looks like the heaviest returns are further south down right around the Washington/Oregon border…..down near Kelso.”

The briefer then revealed to the pilot that there were a number of radar returns in his area, on the east side of the Cascades, and that the precipitation and cloud cover would drop off over the course of the flight. Lewiston was reporting a ceiling of 6,000 feet and a few clouds below that at 4,200 with strong winds there; winds were 140 degrees at 17 knot with gusts to 29 knots, with winds variable between 110 to 220 degrees. The forecast was for broken clouds, 3,500 feet layered to FL250, with occasionally broken clouds at 2,500, scattered moderate rain showers, and winds out of the south with gusts up to 25 knots. Scattered to moderate rain showers were also forecast over the Cascades, with a broken layer of clouds at 6,000 feet layered to FL250. East of the Cascades the forecast was for broken clouds at 8,000 feet with tops at 12,000 feet, and further east broken clouds at 8,000 feet layered to FL250, with isolated moderate rain showers.

The briefer advised the pilot that for his destination forecast into LWS, from his departure time up until 1100 local time, the forecast indicated winds 190 at 7 knots, visibility greater than six miles, showers in the vicinity, broken ceilings 4,000 feet, overcast clouds 9,000 feet, and wind shear potential at 15,000 feet with winds 250 degrees at 30 knots.

The briefer then gave the pilot winds aloft for 13,000 feet, which indicated that out of the Seattle area the winds were 250 at 30 knots, and once he made it into eastern Washington, the winds would be 270 degrees at 27 knots. The controller also advised the pilot that when entering the Lewiston area, he could expect winds 290 degrees at 34 knots. The pilot replied, “Oh. Gee whiz.”

The closest weather reporting facility to the accident site was located at Chehalis-Centralia Airport (CLS), Chehalis, Washington, which is about 36 nm west of the accident site. About 0735, Automated Weather Observing System (AWOS) reporting wind 210 degrees at 5 knots, visibility 5 miles, light rain showers, scattered clouds at 2,100 feet, broken clouds at 2,800 feet, and overcast clouds at 3,700 feet, temperature 09 degrees Celsius (C), dew point 09 degrees C, and an altimeter 29.69 inches of mercury.

The onsite examination of the wreckage revealed fragmented portions of the cockpit and engine components in a 5-foot-deep impact crater, located on a 30-degree slope of a densely forested mountain. Several hundred components were also found scattered over the 20 to 30-degree down sloping terrain within the 160-foot-long debris field, which fanned out over a 45-degree arc from the main impact area. The examination further revealed the airplane to have been in a near vertical orientation, and in a slightly right-wing-low attitude. The impact crater measured 40 feet long, 15 feet wide and 5 feet deep was documented. The longitudinal axis of the airplane aligned with a magnetic heading of 330 degrees, while the top of the airplane was aligned along a 060 degree heading. The energy path was oriented on a magnetic heading of about 060 degrees, and measured to be about 300 feet long and 150 feet wide.

A survey of the accident site, under the supervision of the IIC, revealed that an 18-inch metal fragment was located about 20 feet south of the main impact crater, and miscellaneous pieces were found about 21 feet east and 25 feet northwest of the crater. Additionally, one engine and a propeller blade were observed about 56 feet east of the impact crater. About 130 feet east-northeast of the depression, airspeed and vertical speed indicator dials were found. Also located was an instrument panel cluster, which was found about 162 feet northeast of the main impact crater. Additionally, an attitude gyro cluster was found about 5 feet further in line with the energy path of the instrument panel cluster.

On November 3, 2010, an autopsy was performed on the pilot at the Lewis County Coroner’s Office, located in Chehalis, Washington. The results of the autopsy revealed that the cause of death was attributed to severe blunt force injuries.

Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report indicated that carbon monoxide and cyanide were not tested for, and that neither ethanol nor drugs were detected in the muscle.

Shadin Digiflo-L Fuel Flow Indicator examination

During the investigation the IIC recovered a Shadin Avionics Digiflo-L Fuel Flow Indicator (part number 91053P, serial number 3749) from the aircraft wreckage. The component was subsequently packaged and shipped to the NTSB Vehicle Recorders Laboratory in Washington, D.C., for examination.

Due to damage from the impact, no data could be recovered from non-volatile memory in the unit. The unit software version was identified as 60.10.84. The identification was based on a label recovered inside the unit.

Aircraft instrument/indicator examinations

During the investigation the IIC recovered the airspeed indicator dial face, the directional gyro dial face, and the Exhaust Gas Temperature (EGT) gauge dial face. All three components were packaged and shipped to the NTSB Materials Laboratory in Washington, D.C., for examination. The materials lab specialist reported that the results of her examination revealed that the dial faces for all three indicators showed no evidence of witness marks from the indicator arms. The specialist added that all three faces were heavily damaged and scratched during the impact sequence, possibly masking any sign of witness marks.

Engine examinations

Engines general

The crankshafts were separated at the first journal on both engines and all accessories were separated from the engine cases during the impact sequence. Both turbochargers and one magneto were recovered. The spark plugs from the right engine displayed carbon deposits. The spark plugs from the left engine displayed signatures that indicated normal operation. Both engines were shipped to the engine manufacturer for further examination.

Right position engine

A Continental Motors, Inc., engine technician reported that an examination of the right engine, model TSIO520NB, serial number 276993, revealed that the engine had varying degrees of impact damage. The technician concluded that as a result of his inspection this engine did not reveal any pre-impact abnormalities that would have prevented normal operation and production of rated horsepower.

Under the supervision of the IIC, the right engine’s turbocharger, serial number ZKN03326, was examined by a technician from Hartzell Engine Technologies. The technician reported that assembly was consistent with the design data and there were no indications that unimproved parts were installed. The technician further reported that the turbocharger did not display signs of thermal distress from internal or external sources. Circumferential scoring on the compressor contour surface along with smearing of compressor vane tips provided possible evidence of foreign object damage (FOD) ingestion during operation. Also the significant wear on the outboard thrust bearing suggest FOD and possible loss of turbo performance prior to impact. The axial coining marks from the compressor impeller blades into the compressor contour surface are consistent with impact.

Left position engine

A Continental Motors, Inc. engine technician reported that an examination of the left engine, model TSIO520NB, serial number 29892, revealed that the engine had varying degrees of impact damage. The technician concluded that as a result of his inspection the engine did not reveal any pre-impact abnormalities that would have prevented normal operations of rated horsepower.

Under the supervision of the IIC, the left engine’s turbocharger, serial number, AIN29892, was examined by a technician from Hartzell Engine Technologies. The technician reported that assembly was consistent with the design data and there was no evidence of mechanical malfunction. There were no indications that bogus parts were installed. The turbocharger did not display signs of thermal distress from internal or external sources.

Propeller examinations

A post-recovery examination of the propellers, which was performed by a Cessna Aircraft Company representative, under the supervision of the NTSB IIC, revealed the following:

The propeller blades separated from the propeller hubs. Five blades were recovered; three from the right propeller and two from the left propeller.

Right propeller

One of the blades displayed leading edge polishing. It was slightly bent and displayed damage to the butt of the blade. About 2 inches of the second blade tip was observed separated. The blade was slightly bent, displayed leading edge polishing, and one leading edge impact nick near the butt of the blade. The third blade displayed leading edge polishing and slight leading edge impact damage, with slight curling at the tip. The blade impacted a tree, which resulted in a 90-degree forward bend. The trailing edge of the blade displayed impact damage, which resulted in a 3 inch section of the blade being folded aft about 90 degrees.

Left propeller

One of the propeller blades was separated about 12 inches from the hub. It displayed leading edge and trailing edge impact damage. The outboard section of the blade was bent forward in a small radius bend of about 60 degrees. The second blade displayed an aft large radius bend of about 30 degrees and impact damage to the leading edge. The impact damage to the left propeller blades appeared to be of a greater magnitude than the damage to the right propeller blades.

Additional propeller examinations

The left and right propeller blades were sent to the manufacturer, McCauley Propeller Systems, Wichita, Kansas, for further evaluation.

In an examination performed by a McCauley Propeller Systems technician, it was reported that the subject propellers were heavily damaged from the impact sequence, and were recovered as five individual blades. None of the blade actuating pins were attached to the blades. Additionally, two hub fragments and a portion of the propeller heat system’s electrical slip ring was recovered. One hub fragment contained a serial number matching the left hand propeller listed in the propeller logbook. The other fragment was a portion of the hub mounting face that contained a threaded steel attach stud. The stud was sheared cleanly at the mounting face during the impact sequence. None of the pitch change system was recovered.

As a result of the examination, the McCauley technician reported that the propeller damage was the result of impact [forces], and that there were no indications of any type of fatigue or other propeller failure prior to impact. The technician further reported that both propellers showed indications of rotation at impact, with the left propeller being operated under conditions of some power at impact, although the exact amount of power was not determined. The technician stated that the right propeller was not operating under significant conditions of power at the time of impact.

While exact blade angles at impact were not determined, impact signature markings indicate that both propellers were operating at or near the latch pitch position at impact. Neither propeller had indications of being in the feathered position at impact. There were no indications of any type of fatigue failure.

The technician revealed that the left propeller blades exhibited S-shaped bending along the span, and that one blade was separated at the mid-span. Both recovered left hand blades had deep leading edge impact marks. The left and right propeller blade butts were found with impact marks from contact with the opposing blade actuating pins and the pitch change links. The technician reported that the position of these marks indicates a propeller blade angle of about latch pitch position at impact. Each of the right hand propeller blade shanks was heavily damaged with deep impressions. The left hand blade shanks were generally less damaged. This lower shank damage level is attributed to a higher rotational energy on the left hand propeller during blade release.

Blade bending, twisting, and overall propeller damage was less extensive for the right propeller and was typical of that associated with low rotational energy at impact. Blade bending, twisting, and overall propeller damage was more extensive for the left propeller and was typical of that associated with higher power at impact.

Airframe examination

Due to the destructive nature of the high energy impact forces associated with this accident, the Cessna Aircraft Company representative revealed that impact damage prevented an evaluation of the following:

Navigation instruments

Electrical systems

Radios and transponder

Fuel system

Cabin and equipment furnishings

Flight controls

Hydraulic system

Environmental systems

Ice protection systems

Engine ignition system

Engine controls

Engine instruments

The FAA Flying Handbook, H-8083-3A states, "Engine failures well above the ground are handled differently than those occurring at lower speeds and altitudes. Cruise airspeed allows better airplane control, and altitude may permit time for a possible diagnosis and remedy of the failure. Maintaining airplane control, however, is still paramount. Airplanes have been lost at altitude due to apparent fixation on the engine problem to the detriment of flying the airplane."