NTSB Factual Report

HISTORY OF FLIGHT

On January 28, 2016, about 1857 Pacific standard time, a Piper PA-24-260C, N9362P, impacted terrain during an instrument landing system (ILS) approach into Charles M. Schulz Airport – Sonoma County Airport (STS), Santa Rosa, California. The commercial pilot and passenger were fatally injured. The airplane was registered to and operated by Tango Charlie Aviation LLC as a 14 Code of Federal Regulations Part 91 flight. Night instrument meteorological conditions prevailed at the time of the accident, and a visual flight rules (VFR) flight plan had been filed for the cross-country flight. The personal flight departed Palm Springs International Airport (PSP), Palm Springs, California, at 1535.

According to witnesses, the pilot and his passenger flew from STS to PSP the day before the accident for an overnight stay. A fixed based operator filled the airplane's fuel tanks to capacity as instructed by the pilot, who anticipated an afternoon departure the following day. On the day of the accident, the pilot filed a VFR flight plan and then departed for STS with VFR flight following. He obtained an instrument flight rules clearance from air traffic control (ATC) about 46 nautical miles (nm) from STS and was subsequently cleared to an approach fix on the ILS approach to runway 32 at STS.

The airplane's final movements were captured by a combination of ATC audio and an onboard Appareo Stratus 2 unit that recorded GPS and altitude heading reference system data on an internal non-volatile flash memory chip. At 1833, the pilot contacted Oakland Air Route Traffic Control Center (ARTCC) and reported that he was VFR at 6,500 ft mean sea level (msl). After acknowledging receipt of the STS altimeter setting, the pilot asked the controller "what are they doing for approaches?" The controller informed the pilot that STS was using the runway 32 ILS approach, and the pilot acknowledged the communication. Two minutes later, the pilot requested an instrument flight rules (IFR) clearance, and the controller reported that she had his request. The airplane crossed Scaggs Island VOR, an initial approach fix on the runway 32 ILS approach, at 1837 and then turned to the LUSEE intersection, an intermediate fix on the approach located 12.2 nm from STS.

During the cruise portion of the flight, the airplane flew directly to the assigned waypoints with minimal course variation in a manner consistent with the pilot using the autopilot. The airplane's course variation became more erratic after the airplane passed DACER intersection, a waypoint located 15.5 nm from Scaggs Island VOR.

At 1840, the controller cleared the pilot to STS via radar vectors and instructed him to turn left for traffic and to descend and maintain 5,000 ft msl. The pilot acknowledged and complied with the controller's instructions as indicated by the GPS data. The ARTCC controller then vectored the pilot back toward the localizer and cleared him to proceed to LUSEE and to maintain 4,500 ft msl. Subsequent GPS data points indicated that the pilot complied with the controller's instructions. At 1850, the pilot was cleared for the runway 32 ILS approach and instructed to cross LUSEE at or above 4,200 ft msl. He acknowledged the instructions and began his descent to the assigned altitude.

At 1851:25, the pilot reported that he missed intercepting the localizer course but was correcting. The controller then advised an STS tower controller that the airplane was arriving late due to the pilot's trouble flying the localizer. The pilot was subsequently handed off to the STS tower controller. GPS data showed that the airplane crossed the final approach fix, located about 6.2 nm from STS, about 1,000 ft above the glideslope intercept altitude. At 1856:06, when the airplane was about 3.3 nm from the airport, the pilot notified the STS tower controller that he was inbound for the ILS. Seconds later, the pilot acknowledged a clearance to land that the controller had issued, which was the pilot's final transmission. About 40 seconds later, the tower controller notified the pilot that he was "drifting right of course" and then informed him that he was "well right of course."

ATC radar data furnished by the FAA was compared to the GPS data points recovered from the Appareo Stratus non-volatile memory unit, which was mounted to the airplane's instrument panel. The two sources produced nearly identical course lines, which showed the airplane intercept LUSEE, an intermediate approach fix, and subsequently maintain a course to the right of the localizer for several nautical miles during the ILS approach. GPS data indicated that the airplane was initially left of the localizer after the airplane crossed PIGPN, the final approach fix. About 2 nm beyond PIGPN the airplane passed to the left side of the localizer. In the next minute, the airplane turned right about 60° and crossed through the localizer, at which time the tower controller reported to the pilot that he was "well right of course." During this time, the airplane's descent rate increased from about 600 feet per minute (fpm) to about 1,200 fpm. The final GPS data points showed the airplane in an approximate 60° left turn, with a 35° nose-down attitude, and on a heading of 302° magnetic. The accident site was about 0.14 nm from the last GPS data point.

PERSONNEL INFORMATION

The pilot held a commercial pilot certificate with ratings for airplane single-engine land and instrument airplane. He held a second-class medical certificate issued on October 22, 2015, at which time he reported 1,278 total flight hours of which 50 hours were within the previous 6 months. The medical certificate included one restriction: "must have available glasses for near vision."

A copy of a spreadsheet the pilot used to record his flight time was furnished by the pilot's friend. According to this flight record, the pilot's last instrument proficiency check (IPC), which was his last instrument flight experience was completed in 1.3 hours on November 6, 2015. The IPC instructor reported that the pilot demonstrated good aeronautical decision-making during their discussion of weather planning but struggled in performance, as he kept his airspeed too high during approaches, which resulted in steeper turns. The spreadsheet showed that the pilot had accumulated a total of 93.6 hours of actual instrument flight experience. Before his most recent IPC, the pilot had accrued 4 hours of actual instrument experience and 3.4 hours of simulated instrument experience in the previous year, most of which was in May 2015. The spreadsheet indicated that the pilot had not accumulated any simulated or actual instrument experience between November 6, 2015, and January 2, 2016, the last recorded entry in the spreadsheet. The spreadsheet showed that he had accrued 0.5 total hours of night flight experience in the preceding 2 years. In his most recent night flight entry, dated November 2015, he noted the flight as "Night Current." His most recent experience flying in night instrument meteorological conditions was documented on March 27, 2013.

The pilot's most recent biennial flight review (BFR) was completed on May 15, 2015. The BFR instructor stated that the pilot demonstrated competency in his decision-making skills and piloting abilities during the flight review.

AIRCRAFT INFORMATION

According to Federal Aviation Administration (FAA) records, the airplane was manufactured in 1969 and registered to the pilot on September 9, 2015.

The airplane was powered by a Lycoming IO-540-N1A5, a normally-aspirated, direct-drive, air-cooled, 260-horsepower engine. A work order obtained from a maintenance facility revealed that the most recent annual inspection was completed on August 20, 2015, at which time the airplane had accumulated 5,284.2 flight hours. The entry listed a tachometer time of 214.2 flight hours at the time of the inspection. The tachometer recovered from the accident site showed 245.1 flight hours, which indicated that the airplane had accumulated 5,315.1 total flight hours at the time of the accident.

According to the manufacturer, the airplane was originally equipped with a Piper Auto Control III autopilot system; the airplane's logbook history did not indicate if the system had been upgraded or replaced. According to the BFR instructor, the airplane was equipped with a two-axis autopilot system when he last flew with the pilot in 2015.

METEOROLOGICAL INFORMATION

STS was equipped with an automated surface observation system, which transmitted Meteorological Aerodrome Reports (METARs) and special reports surrounding the period of the accident. The observations indicated that VFR weather conditions prevailed at STS in the early afternoon, followed by a deterioration to IFR from the pilot's time of departure until the time of the accident, followed by low IFR (LIFR) conditions about 4 minutes after the accident. LIFR conditions are defined as a ceiling less than 500 ft and/or visibility of 1/2 mile or less.

Multiple special reports for STS were issued throughout the period of the flight, all indicating decreasing visibility and ceilings. The final special report issued before the accident was at 1853 and indicated calm winds, 2 1/2 miles visibility, mist, scattered clouds at 400 ft, an overcast ceiling at 900 ft,and a temperature and dewpoint of 12°C.

A special METAR was issued about 4 minutes after the accident that indicated calm winds, visibility 2 1/2 miles, mist, an overcast cloud layer at 400 ft, and a temperature and dewpoint of 12°C.

Forecasts

The area forecast for the northern California area at the time of the accident included broken clouds at 2,000 ft msl with tops to 6,000 ft msl and isolated rain showers with an outlook of instrument meteorological condition ceilings.

AIRMETs (airmen's meteorological information) for the accident period revealed that the accident site was located within an area covered by an advisory for mountain obscuration and near the border of an active AIRMET for IFR conditions.

A terminal area forecast (TAF) that was issued on the morning of the accident for STS indicated deteriorating weather up until the time of the accident; however, the forecast was not for IFR conditions. At the time of the pilot's departure, the TAF reported marginal VFR to IFR conditions for the hours that followed the pilot's estimated arrival time.

Weather Briefing

The pilot retrieved weather information from the online service, ForeFlight.com, about 24 hours before he departed on the flight. According to Lockheed Martin Flight Services, the weather information provided to the pilot included TAFs, AIRMETs, area forecasts, METARs, and Notices to Airmen (NOTAMs). The area forecast report for Northern California, valid until the morning of the flight, indicated VFR conditions. The TAF for STS, valid to midnight, showed deteriorating conditions with low ceilings and low visibility.

The United States Naval Observatory reported the moon phase as a waning gibbous moon with 79% of the moon's visible disk illuminated. The moonset for Santa Rosa, California, was at 0948 and moonrise was at 2215.

AIDS TO NAVIGATION

The ILS runway 32 approach had a final approach course of 321° magnetic, three initial approach fixes, and a decision height of 377 ft msl (249 ft agl). The pilot was vectored directly to an intermediate approach fix, LUSEE, located at the intersection of the localizer and two separate VOR radials, 12.2 nm from the airport. PIGPN was the final approach fix and the glideslope intercept waypoint at an intercept altitude of 2,000 ft msl. The published landing minimums for the approach required a minimum runway visual range of 2,400 ft.

AIRPORT INFORMATION

STS was located about 1.5 nm north-northwest of the accident site at an elevation of 129 ft. Runway 32/14 was 6,000 ft long and 150 ft wide. The airport was located within class D airspace and publicly owned and operated by the County of Sonoma. The airport was serviced by an operating control tower at the time of the accident.

The airport had several published NOTAMs at the time of the accident. One instrument NOTAM, which was valid at the time, stated "Instrument Approach Procedure ILS OR LOC/DME RWY 32, AMDT 19... DME REQUIRED EXCEPT FOR AIRCRAFT EQUIPPED WITH SUITABLE RNAV SYSTEM WITH GPS, PYE VOR OUT OF SERVICE."

WRECKAGE AND IMPACT INFORMATION

The airplane impacted a grass field about 1.5 nm south of STS. All major components of the airplane were accounted for at the accident site. An initial impact point that spanned about 2 ft in length was identified by fragments from the left wing and the red position light. The main wreckage was located in the debris path about 133 ft from the initial impact point beyond an intermediate impact crater. Portions of the left wing, including two breached fuel tanks, were located about 40 ft south of the main wreckage. The empennage was inverted but remained intact with some airframe skin deformation to the vertical stabilizer, rudder and stabilator.

Airframe and Engine Examination

The main wreckage was comprised of the cockpit, right wing, a portion of the left wing, and engine. The rudder, aileron, and stabilator cables were traced from the cockpit to their respective control surfaces. The flap jackscrew displayed 17 threads, consistent with a 10° flap setting. The stabilator pitch trim jackscrew inner shaft top extension was about 0.35 inches, consistent with a neutral pitch setting.

Both the left main and auxiliary fuel tanks were breached and void of fuel. The right main tank remained intact; however, its fuel line was open. The right auxiliary tank contained about 8 gallons of liquid that had an odor and color consistent with 100 LL aviation grade gasoline. The fuel selector, which was positioned on the left main fuel tank, was subsequently rotated to each of the four fuel tank ports, and no obstructions were observed.

The main landing gear were attached to their respective wings, and the nose landing gear came to rest about 100 ft forward of the engine. The main landing gear control cables were impact damaged and extended about 8 inches from the outer cable shroud, consistent with a gear extended position.

A heading indicator and two attitude indicators were disassembled and examined at the accident site. The pendulous vane housings and vanes all exhibited light circumferential scoring. The vacuum pump functioned normally when manipulated by hand; both the vanes and carbon rotor were intact and unremarkable. The autopilot mode selector was found in the HDG position at the accident site.

The engine displayed a crack in the engine case between the No. 1 and No. 3 cylinder and around the No. 2 cylinder. All six cylinders remained attached to the engine crankcase. The fuel injection servo and air intake screen separated from the engine, and the left magneto and the oil filter were partially separated.

Rotational continuity was established throughout the engine and valve train when the engine crankshaft was manually rotated at the propeller. Thumb compression and suction were obtained on all six cylinders. The cylinder combustion chambers and barrels were examined with a lighted borescope, and no evidence of foreign object ingestion or detonation was observed. The combustion chambers displayed color signatures consistent with normal operation. Examination of the rocker arms revealed no evidence of unusual wear.

An examination of the top and bottom spark plugs revealed signatures consistent with normal wear. The oil filter exhibited impact damage and partial separation. The oil sump pick up screen was removed and examined, but did not display any blockage. The engine driven fuel pump had partially separated, but suction and pressure were obtained when it was manipulated manually as water and mud were dispensed from the output port.

The fuel flow divider was disassembled and examined; about 1 tablespoon of residual fuel was observed in the divider housing. All six of the fuel nozzles were removed, and no obstructions were observed.

The fuel injection servo was separated and displayed impact damage at the throttle body near the throttle plate. An inspection of the fuel

NTSB Probable Cause

The pilot’s failure to maintain airplane control during an instrument approach in night instrument meteorological conditions, which resulted in a collision with terrain. Contributing to the accident was the pilot’s lack of recent experience in night instrument meteorological conditions.