Verified accident record: NTSB WPR11FA316, Watsonville

Four North Aero documents teach from this accident, and before this page existed three of them disagreed about it: the private pilot spin lesson plan said one thing, its own question bank said another, and the two decision trees said a third. A candidate reading two of them met two different accidents.

In the CFI curriculum, only lesson 6 uses it, at element 10, through the decision trees. Lessons 31, 32 and 33 cite AC 61-67C and teach stalls and spins but state no facts about this accident, and they should not start doing so without citing this page.

Nothing may state a fact about this accident that is not on this page. If a fact is needed that is not here, it is read from the report and added here first.

The pilot

The pilot failed the private pilot practical test twice before passing. First attempt February 11, 2011, at 57.4 hours. Second attempt March 1, 2011, at 69.0 hours. One of the unsatisfactory areas on the second attempt was "Performance Maneuver, Steep Turns." He was retested on March 17 and his performance was satisfactory and in compliance with applicable FAA requirements.

The sequence

Departed WVI runway 20, directly towards the cloud layer. A fog and stratus layer typical for the locale and season had moved inland from the Pacific and sat just southwest of the airport. One pilot witness put the boundary of the layer at California Highway 1, perpendicular to runway 2/20 just west southwest of the departure end.

Eyewitnesses and recovered GPS data show the airplane began a sharp left turn before reaching the end of the runway, at about 400 feet AGL. Two witnesses observed a very rapid left roll when the airplane was approximately 500 feet above the departure end of runway 20. It rolled until nearly inverted, the nose dropped, and it descended rapidly through about two tight turns or spirals, appearing to begin to recover before disappearing behind trees.

The airplane did not enter the cloud.

First impact was a parking lot about 700 feet southeast of the departure end of runway 20, then about 130 feet east-southeast into the building. Parallel slash marks in the pavement were consistent with propeller strikes from an engine that was developing power. Post-accident examination revealed no anomalies or failures that would have precluded normal operation.

The pilot's decision to conduct a takeoff towards a nearby low-lying cloud layer, and his failure to maintain aircraft control during the subsequent turn, stall, and spin during his attempt to avoid the cloud layer. Contributing to the accident was the pilot's inability to recognize an incipient stall, and prevent the full stall. His ability to recognize and prevent the stall was hindered by an inaudible stall warning system of questionable accuracy.

Findings: decision making and judgment, pilot. Aircraft control, pilot. Personnel issues, general, pilot. Aircraft: angle of attack, not attained or maintained.

Both numbers are in the report and they describe different moments. This was never a contradiction; it was two documents each quoting a different instant and neither saying which.

• 400 feet AGL is where the sharp left turn began, from GPS data and eyewitnesses.
• About 500 feet above the departure end of runway 20 is where two witnesses saw the very rapid left roll begin.

Cite the moment, not just the number. "Turned at 400 feet AGL and was rolling by about 500 feet" is correct and is more useful teaching than either figure alone, because the gap between them is the whole margin the pilot had.

Each of these is a teaching point that was sitting in the docket unused.

1. He had two weather briefings. The pilot contacted Lockheed Martin Flight Services by telephone at about 1023 and again at about 1417 on the day of the accident. This is not a no-briefing accident, which makes it far more useful than one, because the briefing did not save him.

2. He departed toward the cloud when three other runways pointed away from it. The airport had two similar-length runways, 2/20 and 8/26, so four departure options. The report states that airplane performance, terrain and obstacle clearance did not preclude a takeoff from any of the four. The investigation could not determine why he chose runway 20, and notes his choice may have been influenced by habit pattern, existing traffic, or a previous taxi event.

3. Runway 20 was the published preferred calm wind runway. That is in the airport's own noise abatement guidance. The runway that pointed at the cloud was the one the airport told pilots to prefer, which turns a simple "why did he pick that runway" into something much closer to how real decisions get made.

4. The turn violated published noise abatement guidance, and that guidance carries its own warning. The guidance prohibited departure turns prior to the airport boundary or below 900 feet AGL. He turned at 400 feet AGL. The same guidance advises pilots that "Safety always supersedes noise abatement procedures."

5. The stall warning system was modified and its accuracy was never established. The vane and switch assembly had been modified and was not installed in accordance with the manufacturer's design drawings. The as-delivered vane position could not be determined and no records of it existed. Post-accident testing found the vane switch and horn functional, but the horn volume was not measured against any standard. The investigation was unable to determine whether the system would have provided sufficient, or any, notification of a stall even if it had been audible.

6. It was inaudible because of headsets, and the owners knew. At least two headsets were in the wreckage, one noise cancelling. According to the co-owner the horn was inaudible to a pilot wearing a headset, and the owners' attempts to rectify that were unsuccessful.

Not yet applied. These are for Erick, and they are in materials/MATERIALS-REVIEW.md as findings 1, 2 and 3.

The question bank is substantially correct and the lesson plan is substantially wrong. That is the opposite of what document seniority would suggest, since the lesson plan is the one an instructor teaches from.

The final report is retrievable from the NTSB CAROL report generator using ProjectID 81041. The docket is at the NTSB Docket Management System under the same ProjectID and holds 31 documents, including stall warning system information, airplane performance information, the pilot weather briefing record and audio, GPS flight track data, pilot logbook excerpts, and eyewitness records of conversation.

Re-verify when: a lesson makes a new factual claim about this accident that is not on this page, or the NTSB issues a revision. This is a closed 2011 investigation and its facts are stable, so this is not a recurring currency check in the way an FAA edition is.

• ✓Final report read in full from the live NTSB source on the date stated
• ✓Probable cause quoted verbatim rather than paraphrased
• ✓The 400 versus 500 disagreement resolved by naming the moment each describes
• ✓Every fact three North Aero documents disagreed on is settled and attributed
• ✓What the record contains that no North Aero document used is listed, since that was the point
• ✓The corrections the record forces are listed rather than silently applied
• ✓No currency figure, no em dash, altitudes in monospace per the design system