Watsonville, CA, USA
N7759M
MOONEY M20F
The pilot departed from his home airport situated about 3 miles east-northeast of the ocean with a low-lying stratus cloud layer. The takeoff was conducted while it was still daylight. Eyewitness and photographic evidence indicated that the stratus layer was nearby, to the southwest, south and southeast of the airport at the time of the takeoff. The airport was non-towered, and was equipped with two similar-length runways, designated as 2/20 and 8/26. Airplane performance, and terrain and obstacle clearance considerations did not preclude a takeoff from any of the four possible runway options. However, the takeoff was conducted from runway 20, directly towards the cloud layer. Eyewitnesses and recovered GPS data indicated that the airplane began a sharp left turn prior to reaching the end of the runway, at an altitude of about 400 feet above ground level (agl). That turn was consistent with an effort to avoid the cloud layer, but contrary to published airport noise abatement guidance that prohibited departure turns prior to the airport boundary, or at altitudes below 900 feet agl. The airplane did not enter the cloud, but during the turn, the airplane stalled, entered a spin, and descended rapidly to the ground. The airplane struck a parking lot and building less than 700 feet from the departure runway. Post-accident examination of the airplane and engine did not reveal any anomalies or failures that would have precluded normal operation. At least two headsets, one of which was a noise cancelling unit, were located in the wreckage. According to the airplane co-owner, the vane-activated, electrically-powered stall warning horn was inaudible to a pilot wearing a headset, and the owners' attempts to rectify that situation were unsuccessful. Post-accident testing of the vane switch and warning horn indicated that they were functional, but the horn volume was not measured or compared to any known standard. During airplane manufacture, the final position of the stall warning vane and switch assembly on the wing is determined during the production flight test of each individual airplane, in order to ensure system activation at the proper angle of attack. No records of the as-delivered vane position were available, and the as-delivered position of the vane could not be discerned by examination of the wreckage. Examination of the vane assembly revealed that it had been modified, and was not installed in accordance with the manufacturer's design drawings. In addition, no information regarding the accuracy of the modified stall warning system was located. The investigation was unable to determine whether the system would have provided sufficient, or even any, notification of a stall, presuming the horn was audible to the pilot, which in this case it was not. Despite three other runway alternatives, the pilot knowingly and intentionally decided to depart from the runway most closely aligned towards the stratus layer, with the apparent plan to turn to avoid it once airborne. While his runway choice may have been influenced by habit pattern, existing traffic, or a previous taxi event at that airport, the investigation was unable to determine why the pilot chose that runway, instead of using any of the other three alternatives which would have taken him away from the cloud layer. He then inadvertently stalled and spun the airplane during the avoidance turn, at an altitude which did not allow recovery.
HISTORY OF FLIGHTOn July 7, 2011, about 1928 Pacific daylight time, a Mooney M-20F, N7759M, was substantially damaged when it impacted a parking lot and a building shortly after takeoff from Watsonville Municipal Airport (WVI), Watsonville, California. The private pilot and the three passengers were fatally injured. The personal flight was operated under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the flight. The airplane was co-owned by the pilot and another individual. According to the co-owner, the airplane was based at WVI. Relatives reported that the pilot, his wife, and their two children planned to travel to Groveland, California, for the weekend. Lockheed Martin Flight Services (LMFS) information indicated that the pilot contacted LMFS by telephone about 1023 on the day of the accident, and again about 1417, to obtain weather briefings. The pilot informed the LMFS representative that his intended destination was Pine Mountain Lake Airport (E45), Groveland. According to multiple information sources, a fog bank/stratus layer that moved inland (towards the airport) from the Pacific Ocean, and was typical for that locale during that time of year, was located just southwest of the airport at the time of the takeoff. That cloud phenomenon was often referred to as the "marine layer." According to information provided by several eyewitnesses, the airplane departed from WVI runway 20. One pilot witness reported that the airplane climb path was shallow, and that the airplane would not clear the stratus layer. Two other witnesses, one of whom was a pilot, in two other separate locations, reported that the climb angle after takeoff appeared "steep." Both observed the airplane commence a very rapid left roll when it was approximately 500 feet above the departure end of runway 20. The airplane appeared to roll until it was "nearly inverted," and the nose "dropped," so that it was pointing towards the ground. It descended rapidly, and completed about two "tight turns" or "spirals" before it appeared to begin to recover, and then disappeared behind trees. Both witnesses observed fire and smoke immediately thereafter. Ground scars indicated that the airplane first impacted a parking lot about 700 feet southeast of the departure end of runway 20, traveled about 130 feet east-southeast, and struck the building. Parallel slash marks in the pavement were consistent with propeller strikes from an engine that was developing power. The airplane structure was severely deformed by the impact, and portions were consumed by post impact fire. PERSONNEL INFORMATIONAccording to Federal Aviation Administration (FAA) records, the pilot was issued his private pilot certificate, with an airplane single engine land rating, on March 17, 2011. His most recent FAA third-class medical certificate was issued in July 2010. The pilot did not pass his first private pilot practical examination on February 11, 2011, at which time he had a total flight experience of 57.4 hours. He also did not pass his second private pilot practical examination on March 1, 2011, at which time he had a total flight experience of 69.0 hours. One of the segments on the second examination that the pilot's performance was determined to be unsatisfactory was "Performance Maneuver - Steep Turns." However, he was retested on that and other aspects on March 17, and his performance was satisfactory, in compliance with applicable FAA requirements. The pilot's original flight logbook was not located. The airplane co-owner provided copies of some pages of the pilot's logbook that he had obtained previously; the most recent entry in those copies was dated April 24, 2011. According to those records, as of that date, the pilot had accrued a total of 151.5 hours of flight experience. Based on the available records, it appeared that the pilot had accrued all but about 15 hours of his experience in the accident airplane. AIRCRAFT INFORMATIONAccording to FAA information, the airplane was manufactured in 1974, and was equipped with a Lycoming IO-360 series engine and a McCauley 3-blade propeller. The airplane was first registered to the pilot and co-owner on November 24, 2010. The most recent annual inspection was completed in August 2010. At that time, the engine/airframe had a total of 3,902.0 hours, and the engine had 303.4 hours since major overhaul. According to the co-owner, on an unspecified date before April 2011, one of the main landing gear doors was damaged while the pilot was taxiing the airplane on an unspecified taxiway at WVI. That door was subsequently repaired. On April 6, 2011, two main landing gear doors were damaged when the pilot landed on an unprepared strip in Mexico. Those two doors and two other main landing gear doors were removed at some point thereafter, and had not been repaired or reinstalled at the time of the accident. No record of the removal was located in the maintenance records. The co-owner reported that there "was never any noticeable flight performance deterioration due to the removal of the doors." METEOROLOGICAL INFORMATIONPilot Weather Briefings According to information and recordings provided by LMFS, on the day of the accident, the pilot called LMFS on two separate occasions to obtain weather information. During the pilot's first call at 1023, he stated that he planned to fly VFR (visual flight rules) from WVI to E45, and had a planned departure time of 1800, which was nearly 1 1/2 hours earlier than his actual departure time. The LMFS briefer informed the pilot that there was an AIRMET for IFR (instrument flight rules) conditions (specifically low ceilings) along the coast that was valid until 2000, and that VFR from the departure airport was not recommended. The briefer told the pilot that there were currently ceilings "as low as 400 feet in the surrounding area." However, the briefer noted that 2000 was "a long way out" from the current time, that the forecast conditions might not occur, and that the forecast update cycle provided for one more update prior to the pilot's planned departure time. The pilot's second call to LMFS at 1417 was initially for an "abbreviated briefing." He again indicated that he was planning an 1800 departure. The previous weather forecast had been revised, and the new forecast called for scattered clouds at 1,000 feet, with the marine layer moving inland about 2100. This briefer noted that there was a "very strong marine layer along the coast," that the "immediate coast was socked in" from about 120 miles north to 100 miles south of WVI, and advised the pilot to "check back in right before you go." The pilot then asked about the forecast for a departure the next morning (Saturday), and was informed that the marine layer was expected to affect WVI until at least 1100. Meteorological Detection Equipment and Observations WVI was equipped with a segmented circle, a wind sock, and an automated surface observation system (ASOS). The segmented circle/wind sock was situated about 500 feet southwest of the intersection of the two runways. The ASOS sensors were located about 200 feet west of the north end of the paved surface of runway 2, near the northern boundary of the airport. According to the National Oceanographic and Atmospheric Administration web site, the ASOS system detects significant meteorological changes, disseminating hourly and special observations via predetermined networks. ASOS routinely and automatically provides computer-generated voice observations directly to aircraft in the vicinity of airports, which is also available via a telephone and data links. ASOS transmits a special report when conditions exceed preselected weather element thresholds. The WVI ASOS included detection and recording of such parameters as sky condition (cloud height and amount) up to 12,000 feet, visibility, and obstructions to vision such as fog and haze. The ASOS ceilometer was a Vaisala Model CT12K, which utilized laser transmission and reflection to determine cloud height. The ceilometer beam width is confined to a divergence of ± 2.5 milliradians, so that at 12,000 feet the beam’s sample area is a circle with a diameter of 60 feet. The ceilometer beam is aimed perpendicular to the local horizontal (i.e., 'straight up'), and does not pivot or sweep. Processing algorithms are used to determine cloud coverage quantifications such as few, scattered, etc. The WVI 1853 (35 minutes before the accident) ASOS observation included winds from 190 degrees at 6 knots; visibility 10 miles, clear skies; temperature 14 degrees C; dew point 12 degrees C; and an altimeter setting of 29.91 inches of mercury. The WVI 1953 (25 minutes after the accident) ASOS observation included winds from 200 degrees at 4 knots; visibility 10 miles, clear skies; temperature 16 degrees C; dew point 12 degrees C; and an altimeter setting of 29.91 inches of mercury. Eyewitness Reports Multiple witnesses reported that the layer of stratus clouds that was typical for the region during that time of year was present just southwest of the airport. One witness, who was a pilot, and who was leaving the airport at the time of the accident, reported that the boundary of the stratus layer appeared to be coincident with California Highway 1, which ran perpendicular to runway 2/20, just west southwest of the departure end of runway 20. Photographic Evidence Photographs taken by first responders in the period between 20 and 26 minutes after the accident show the stratus layer to the south and east of the accident site. Although a qualitative assessment only, the stratus layer appears to be quite close to the accident site. Airport Manager Information The airport manager, who was also a certificated flight instructor (CFI), described the WVI weather conditions as follows: "Standard Central Coast [weather]; characterized from May to September with coastal stratus in the morning, clearing by noon with the potential to roll back in during early evening or on occasion remain clear till late evening, then slowly building up." He also noted that the local WVI "pilot community is aware of these conditions and the departure/arrival options if you are VFR only…. CFIs take great pains in flying with students during this time to reinforce that the fog is insidious and deceptive." He also noted the importance for local pilots to obtain and understand temperature/dew point spread, cloud clearance, and cross-wind runway information. Refer to the docket associated with this accident for additional meteorological information. AIRPORT INFORMATIONAccording to FAA information, the airplane was manufactured in 1974, and was equipped with a Lycoming IO-360 series engine and a McCauley 3-blade propeller. The airplane was first registered to the pilot and co-owner on November 24, 2010. The most recent annual inspection was completed in August 2010. At that time, the engine/airframe had a total of 3,902.0 hours, and the engine had 303.4 hours since major overhaul. According to the co-owner, on an unspecified date before April 2011, one of the main landing gear doors was damaged while the pilot was taxiing the airplane on an unspecified taxiway at WVI. That door was subsequently repaired. On April 6, 2011, two main landing gear doors were damaged when the pilot landed on an unprepared strip in Mexico. Those two doors and two other main landing gear doors were removed at some point thereafter, and had not been repaired or reinstalled at the time of the accident. No record of the removal was located in the maintenance records. The co-owner reported that there "was never any noticeable flight performance deterioration due to the removal of the doors." WRECKAGE AND IMPACT INFORMATIONThe airplane impacted a parking lot and then a building of an annex of Watsonville Community Hospital. The initial impact location was 677 feet, on a true bearing of 131 degrees, from the center of the departure end of runway 20. The initial impact point was about 130 feet from the building, and the building impact point was on a bearing of 113 degrees true from the initial impact point. Ground scars were consistent with the airplane striking the parking lot in a relatively level, upright attitude. Pavement scars and markings were consistent with the main landing gear being in the retracted position at ground impact, and the engine developing significant power. A fire erupted after impact, and damaged or consumed portions of the airplane, which remained partially embedded in the building. The engine mount, cowl, and propeller were severely disrupted by the impact. The engine was essentially intact, but had sustained crush damage in the aft and up directions. Several engine accessories were fracture-separated from the engine. No abnormal oil deposits or streaking were observed on the internal engine compartment areas, or on the airplane exterior surfaces. The propeller hub was highly fragmented, and none of the three blades was retained in the hub. All three propeller blades exhibited significant bending/twisting deformation, scoring, and gouging. There was no evidence of any pre-impact failures or malfunctions of the engine or propeller that would have precluded continued normal operation and flight. The fuselage was found on its left side, with the inboard section of the left wing located under the airplane, and the outboard section of the left wing fracture-separated from the airplane. The right wing was completely separated from the airplane at the wing root, and was found outside the building. The fuel cap for the right wing tank was absent from its receptacle, and was not located on site, despite multiple searches. A ground search of WVI did not locate the fuel cap. However, sooting patterns on the cap receptacle in the wing were consistent with the cap being in place for at least a portion of the sooting period. The flaps were determined to be retracted at the time of impact. No main landing gear doors were located on scene The empennage was partially intact, with the left horizontal stabilizer fracture-separated from it, and the vertical stabilizer bent about 90 degrees near the mid span station. The as-found extension of the pitch trim actuator was consistent with a normal take-off trim setting. All primary and secondary aerodynamic and flight control surfaces, and their balance weights, were located at the accident site. Partial control continuity was established for the right aileron, right elevator, and rudder. Damage precluded additional control continuity determination. The cockpit/cabin was severely deformed by the impact, and was almost completely separated from the wing structure. The two front seats remained partially attached to their cabin floor attach points, but the rear bench seat was separated from the cabin floor, and was found forward of the front seats. The pilot and younger son were seated in the front left and right seats, respectively. Both front seat occupants' lap and shoulder harnesses were found fastened/buckled and affixed to their respective cabin attach points. The mother and older son were seated in the aft bench seat. Both rear seat occupants' lap belts were found fastened/buckled, but had separated from their respective cabin attach points. The rear seats were not equipped with shoulder harnesses. At least two headsets were found in the wreckage; one appeared to be a Lightspeed Zulu active noise reduction model, and one was a David Clark brand. Both appeared to have been in use at the time of the accident. The throttle, propeller, and mixture controls were retained in the cockpit mount, and attached to their respective actuation cables. Engine cable continuity could not be determined due to impact damage. Both control yokes were present but impact and fire damaged. Most instruments on the pilot-side panel were impact and/or fire damaged. A Garmin GPSMap 396, a JPI model EDM-800 engine analyzer, and a Horizon Instruments P-1000 Digital Engine Tachometer were recovered and sent to the NTSB Recorders Laboratory in Washington DC for data download. The GPS data was successfully downloaded, and the data and results are discussed later in this
The pilot's decision to take off toward a nearby low cloud layer and the subsequent turn, stall, and spin during the pilot’s attempt to avoid the cloud layer. Contributing to the accident was the pilot's failure to avoid the stall. His ability to avoid the stall was hindered by an inaudible stall warning system of questionable accuracy.
Source: NTSB Aviation Accident Database
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