# NTSB WPR11LA094: Rockwell International S-2R, N4977X, Oakley, CA, January 10, 2011 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: January 10, 2011, 10:57 local (18:57 UTC) - Place: Oakley, CA - Coordinates: 38.077777, -121.613334 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.0778&lon=-121.6133&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report January 17, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - Safety recommendations: Yes - NTSB case key (mKey): 78136 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA094 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78136/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78136 - Page: https://openairdocs.org/ntsb/WPR11LA094 ## Probable cause An in-flight collision with an unmarked meteorological evaluation tower (MET) during an aerial application flight due to the pilot's failure to see and avoid the obstacle. Contributing to the accident was the lack of visual conspicuity of the MET and the lack of information available to the pilot about the MET before the flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Object/animal/substance: tower/antenna (incl guy wires)](https://openairdocs.org/ntsb-findings/03022017): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Rockwell International S-2R, 2 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md?model=7630202), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md) - [Oversight](https://openairdocs.org/ntsb-findings/04032000): Organizational issues › Support/oversight/monitoring · FAA/Regulator (probable cause); cases with it: [Rockwell International S-2R, 1 case](https://openairdocs.org/ntsb-findings/04032000/cases.md?model=7630202), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/04032000/cases.md) - [Object/animal/substance: tower/antenna (incl guy wires)](https://openairdocs.org/ntsb-findings/03022017): Environmental issues › Physical environment · Response/compensation (probable cause); cases with it: [Rockwell International S-2R, 2 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md?model=7630202), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md) - [Perception/orientation/illusion: perception](https://openairdocs.org/ntsb-findings/02022040): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Rockwell International S-2R, 1 case](https://openairdocs.org/ntsb-findings/02022040/cases.md?model=7630202), [All aircraft, 61 cases](https://openairdocs.org/ntsb-findings/02022040/cases.md) - [Object/animal/substance: tower/antenna (incl guy wires)](https://openairdocs.org/ntsb-findings/03022017): Environmental issues › Physical environment · Availability of related info (probable cause); cases with it: [Rockwell International S-2R, 2 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md?model=7630202), [All aircraft, 55 cases](https://openairdocs.org/ntsb-findings/03022017/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Rockwell International S-2R, 7 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7630202), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot was initiating an aerial application to a field when the airplane collided with a 198-foot-tall, unpainted metal meteorological evaluation tower (MET). No information about the MET was distributed in any Federal Aviation Administration (FAA) notices or other publications for pilots, and the MET was not equipped with any markings or obstruction lights for visual conspicuity. For these reasons, the pilot likely had limited opportunity to become aware of the MET before the flight, and his ability to detect it visually in flight was extremely limited. Although the pilot’s toxicological results were positive for dextromethorphan (an over-the-counter cough suppressant) and dextrorphan (a metabolite of dextromethorphan) in the urine, the substances were not noted in the blood; therefore, it is likely that some time had passed since the pilot had used the medication. Additionally, these substances would not normally be expected to result in any impairment. METs are used to measure wind data throughout the United States. They can be assembled quickly and can be constructed of galvanized tubing with guy wires used as support. Because many METs (like the accident MET) are just below the 200-foot threshold at which FAA regulations would require the applicant to notify the FAA of the MET and to provide a lighting and marking plan for FAA assessment, many METs are unmarked, unlighted, and not referenced in any FAA notices or publications for pilots. Although the FAA in 2011 approved an update to Advisory Circular (AC) 70/7460-1K, Obstruction Marking and Lighting, that will provide recommended guidance on marking METs, ACs are only advisory in nature. Because of this, MET constructions will likely continue to meet only the minimum requirements and, thus, will remain a hazard to pilots operating at low altitudes. In March 2011, the NTSB published Safety Alert SA-016 to educate pilots about the flight-safety issues presented by METs. The Safety Alert is available at the NTSB’s website at http://www.ntsb.gov/safety/safety_alerts.html. ## Factual narrative HISTORY OF FLIGHT On January 10, 2011, at 1057 Pacific standard time, N4977X, a Rockwell International S-2R, impacted a meteorological evaluation tower (MET) while initiating an aerial application on Webb Tract Island, Oakley, California. The airplane sustained substantial damage. The commercial pilot was fatally injured. Alexander Ag Flying Service Incorporated was operating the airplane under the provisions of Title 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed, and no flight plan was filed. According to the Federal Aviation Administration inspector that responded to the accident site, the pilot was conducting an aerial application when the accident occurred. Witnesses indicated that the pilot overflew the area and then began the first pass over the field. The airplane then impacted a MET. Witnesses did not report seeing the airplane perform any evasive maneuvers prior to the impact. The tower was unpainted metal, and was not equipped with obstruction lights or markings. The land owner indicated that the MET on Webb Tract Island was erected in April 2009. According to Contra Costa Country personnel that approved the construction of the MET, the permit was approved in August 2008, and applicable until August 2009. There was no extension on the permit. The project description stated that the tower stood 197 feet 8.25 inches tall, and was designed specifically for wind resource measurements. Additionally, it stated "The 60-meter (197 feet) tower is lower than the 200 feet threshold set by the FAA, and as such meets FAA regulations." PERSONNEL INFORMATION The pilot, age 58, held a commercial pilot certificate for airplane single and multi-engine land with an instrument rating. He held a second-class airman medical certificate issued on October 13, 2010, with no limitations. The pilot reported 26,000 total flight hours on his last medical application. MEDICAL INFORMATION An autopsy was performed on the pilot on January 11, 2011, by the Office of the Sheriff- Contra Costa County Coroner's Division. The autopsy attributed the cause of death to trauma sustained in the aircraft accident. Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report was negative for carbon monoxide, cyanide, and ethanol. The toxicology report indicated that dextromethorphan, dextrorphan, and ibuprofen were detected in urine. The dextromethorphan and dextrorphan were not detected in blood. ADDITIONAL INFORMATION Meteorological Evaluation Towers (METs) METs are used nationwide to measure wind data. According to a National Agricultural Aviation Association article on METs, "Met testing towers are used for gathering wind data during the development and siting of wind energy conversion facilities. The met towers consist of galvanized tubing assembled at the site, and raised and supported using guy wires. Agricultural pilots, emergencymedical services (EMS) operations, Fish and Wildlife, animal damage control, aerial fire suppression, and any other low-level flying operation may be affected. The fact that these towers are narrow, unmarked, and grey in color makes for a structure that is nearly invisible under some atmospheric conditions." Review of accident data involving aircraft colliding with METs showed that in addition to this accident, two other fatal accidents occurred. One was in 2005 in Ralls, Texas (NTSB accident number: DFW05LA126) and the other was in 2003 in Vansycle, Oregon (NTSB accident number: SEA04LA027). State Actions Prior to FAA action, numerous states took action to mandate requirements for METs at the local level. Examples of these actions include South Dakota requiring that METs be marked, and Wyoming maintaining an online database of METS and requiring all METs to be registered and marked so that they are visible from a distance of 2,000 feet. State and national industry groups also worked with the FAA on recognition of the hazards posed by METs to aircraft operating at low altitudes. FAA Guidance on METs Title 14 CFR Part 77.13 "Construction or alteration requiring notice" states "(a) Except as provided in 77.15, each sponsor who proposes any of the following construction or alteration shall notify the Administrator in the form and manner prescribed in 77.17: (1) Any construction or alteration of more than 200 feet in height above the ground level at its site." In January of 2011, the FAA issued a notice of proposed rulemaking (docket number FAA-2010-1326) to update Advisory Circular (AC) 70/7460-1K, Obstruction Marking and Lighting, to recommend the marking of METs. In June of 2011, the FAA approved the recommended guidance for voluntary marking of METs to be provided in the update AC 70/7460-1K. ACs are advisory and not regulatory. Regional FAA FAAST teams have been educating operators about the dangers of METs. This has been accomplished through presentations, as well as through distribution of brochures highlighting the issue. ## Aircraft - Registration: [N4977X](https://openairdocs.org/deregistered/N4977X-2018-05-30), registration cancelled 2018-05-30, S/N 5022R, built 1975 (OpenAirDocs) - Reported make and model: ROCKWELL INTERNATIONAL S-2R - Registry model: [Rockwell International S-2R](https://openairdocs.org/model/rockwell-international-s-2r) (registry code 7630202) (OpenAirDocs) - Registry engine: [Wright C7BA series](https://openairdocs.org/engine/wright-c7ba-series) (registry code 67017, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 5022R - Airframe hours: 7362 - Engines: Honeywell TPE-331 turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Alexander Ag Flying Service Inc - Registered owner: Alexander Ag Flying Service Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 7, 2010 - Departed: 9CL9, Walnut Grove, CA - Destination: Oakley, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: fatal; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: center; toxicology performed; flight hours: 26,000 total ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 8 knots, gusting 14 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 45 °F, dew point 27 °F - Altimeter: 30.25 inHg - Observed at: CCR, 22 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20110110000469A](https://openairdocs.org/incident/20110110000469A), Jan 10, 2011: Rockwell In S-2R, Oakley, CA, Destroyed, 1 fatal. On JANUARY10, 2011, at 1057 PST, a Rockwell S2R N4977X registered to alexander ag flying was flying below 200 feet heading approximately 210 degrees as he flew… ## Other investigations on N4977X (2) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB LAX94LA158](https://openairdocs.org/ntsb/LAX94LA158), Mar 11, 1994: Rockwell S-2R (N4977X), Tacna, AZ, substantial damage. Probable cause: a catastrophic internal engine failure for undetermined reasons. A factor in the accident was the dark nighttime lighting conditions. - [NTSB LAX89DUJ10](https://openairdocs.org/ntsb/LAX89DUJ10), Sep 14, 1989: Ayres S-2R (N4977X), Yuma, AZ, substantial damage. Probable cause: THE FAILURE OF THE PILOT TO MAINTAIN DIRECTIONAL CONTROL AFTER LANDING ON A DRY GRAVEL RUNWAY. ## Docket (17 files) The files NTSB released with the investigation on November 28, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78136. 8.4 MB in all. - Tower Permit (item 1, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353121&FileExtension=.PDF&FileName=Tower%20Permit-Redacted.PDF - FAA Record of Conversation (item 2, .PDF, 19 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357201&FileExtension=.PDF&FileName=FAA%20Record%20of%20Conversation-Master.PDF - Planner Record of Conversation (item 3, .PDF, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357202&FileExtension=.PDF&FileName=Planner%20Record%20of%20Conversation-Master.PDF - FAA Proposed Revision to AC 70/7460 (item 4, .PDF, 149 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353122&FileExtension=.PDF&FileName=FAA%20Proposed%20Revision%20to%20AC%2070%2F7460-Master.PDF - FAA July 2011 Policy Change (item 5, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353123&FileExtension=.PDF&FileName=FAA%20July%202011%20Policy%20Change-Master.PDF - Advisory Circular 70/7460 (item 6, .PDF, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353124&FileExtension=.PDF&FileName=Advisory%20Circular%2070%2F7460-Master.PDF - NAAA Description of METs (item 7, .PDF, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353126&FileExtension=.PDF&FileName=NAAA%20Description%20of%20METs-Master.PDF - NTSB MET Safety Alert (item 8, .PDF, 115 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353127&FileExtension=.PDF&FileName=NTSB%20MET%20Safety%20Alert-Master.PDF - Toxicological Report (item 9, .PDF, 118 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40355405&FileExtension=.PDF&FileName=Toxicological%20Report-Master.PDF - Photo 1. Wreckage with MET (item 10, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353125&FileExtension=.PDF&FileName=Photo%201.%20Wreckage%20with%20MET-Master.PDF - Photo 2. View from Road Showing Wreckage and MET (item 11, .PDF, 782 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356319&FileExtension=.PDF&FileName=Photo%202.%20View%20from%20Road%20Showing%20Wreckage%20and%20MET-Master.PDF - Photo 3. Separation of MET (item 12, .PDF, 282 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356321&FileExtension=.PDF&FileName=Photo%203.%20Separation%20of%20MET-Master.PDF - Photo 4. Close up Wreckage View with MET (item 13, .PDF, 796 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356322&FileExtension=.PDF&FileName=Photo%204.%20Close%20up%20Wreckage%20View%20with%20MET-Master.PDF - Safety Recommendation Transmittal Letter A-13-016-017 (item 14, .PDF, 192 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395250&FileExtension=.PDF&FileName=Safety%20Recommendation%20Transmittal%20Letter%20A-13-016-017-Master.PDF - Safety Recommendation Transmittal Letter A-13-018-019 (item 15, .PDF, 186 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395252&FileExtension=.PDF&FileName=Safety%20Recommendation%20Transmittal%20Letter%20A-13-018-019-Master.PDF - Safety Recommendation Transmittal Letter A-13-020 (item 16, .PDF, 193 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395254&FileExtension=.PDF&FileName=Safety%20Recommendation%20Transmittal%20Letter%20A-13-020-Master.PDF - Safety Recommendation Transmittal Letter A-13-021 (item 17, .PDF, 505 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395255&FileExtension=.PDF&FileName=Safety%20Recommendation%20Transmittal%20Letter%20A-13-021-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.