# NTSB LAX96LA152: Powell Glasair, N59LP, Groveland, CA, April 2, 1996 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: April 2, 1996, 10:58 local (18:58 UTC) - Place: Groveland, CA - Coordinates: 37.849895, -120.01091 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.8499&lon=-120.0109&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report February 1, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 29405 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX96LA152 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/29405/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=29405 - Page: https://openairdocs.org/ntsb/LAX96LA152 ## Probable cause the pilot's decision to fly the aircraft with a known mechanical discrepancy in the throttle linkage, which resulted in a partial loss of engine power; and his failure to maintain an adequate airspeed while maneuvering for an emergency landing, which resulted in an inadvertent stall/spin. Inadequate maintenance/annual inspection was a related factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, climb - maintenance,annual inspection - inadequate, owner/pilot mechanic (contributing factor) - throttle/power lever,cable - loose (cause) - operation with known deficiencies in equipment - attempted, owner/pilot mechanic (cause) - Forced landing, emergency descent/landing - Loss of control - in flight, emergency descent/landing - airspeed - not maintained, pilot in command (cause) - stall/spin - inadvertent, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled ## Analysis The pilot (part owner of the aircraft) held an A&P certificate & had completed a condition/annual inspection of the aircraft before the flight. The aircraft co-owner stated there was a problem with the throttle cable, & the pilot was going to order a new one, but had not yet done so. Witnesses said the aircraft departed straight out after takeoff. About 4 minutes later, it entered a downwind to the pattern, low & very close to the runway. The witnesses estimated the aircraft's altitude was between 200 and 300 feet agl. At first, some witnesses thought the pilot was going to make a downwind landing on the runway. The witnesses said the aircraft made a tight turn from downwind to base. During the base-to-final turn, the right wing dropped, and the aircraft entered a nose-down descent and crashed. The witnesses heard the engine running before impact, but they described the sound as 'not full power.' An examination of the engine & controls revealed that a clip, which secured the accelerator pump plunger to its actuation shaft in the carburetor, was missing & the pump was inoperative. The throttle cable housing/actuating shaft at the carburetor end was found separated from the cable sheath, exposing the unsupported inside cable. A piece of welding rod was found bent around the housing end & taped to the sheath. The cable was removed from the aircraft & operationally tested. During push-pull tests, the carburetor end would sometimes move an amount corresponding to the cockpit end input; at other times, the carburetor end would move only slightly. ## Factual narrative On April 2, 1996, at 1058 hours Pacific standard time, a Powell Glasair homebuilt experimental airplane, N59LP, collided with trees and the ground following a loss of control during the base-to-final turn at the Pine Mountain Lake Airport, Groveland, California. The aircraft was owned and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the local area personal flight. The aircraft was destroyed in the collision sequence. The private pilot, the sole occupant, sustained fatal injuries. The flight originated from the airport about 4 minutes prior to the accident. Ground witnesses said the aircraft departed straight out following takeoff. About 4 minutes later, it made a downwind entry to the pattern "low and very close to the runway." The witnesses consistently estimated the aircraft's altitude as between 200 and 300 feet agl. One witness said the aircraft was so close that at first he thought the pilot was going to make a downwind landing on the runway. The witnesses said the aircraft made a tight turn from downwind to base. During the base-to-final turn, the right wing dropped and the aircraft entered a nose-down vertical descent to ground impact in a tree. The witnesses said they heard engine sounds throughout, however, they were described as "not full power." The pilot holds an FAA Airframe and Powerplant mechanics certificate. Immediately prior to the accident flight, the pilot completed a condition/annual inspection on the aircraft and the airframe and engine logbooks were annotated to reflect the inspection. During a telephone interview, the aircraft co-owner stated that they had been having problems with the throttle cable and the pilot was going to order a new one. An FAA airworthiness inspector responded to the accident site and interviewed witnesses and examined the wreckage. The engine portion of the wreckage examination was conducted with the assistance of a technical representative from Textron Lycoming Engines. Their respective reports are attached to this report. The FAA inspector reported that he found no discrepancies with the aircraft's control system. Fuel was found in the aircraft tanks and all lines to the carburetor. The engine crankshaft rotated easily by hand, with compression developed in each cylinder. Accessory gear and valve train continuity was established throughout the engine, with normal valve lift developed. Both magnetos were timed to 25 degrees before top dead center and produced strong sparks at each ignition lead. The examination report notes that the spark plugs exhibited normal operating signatures and the induction system was free of obstructions. No discrepancies were found with the fuel pump. Disassembly of the carburetor revealed that the clip which secures the accelerator pump plunger to its actuation shaft was missing and the pump was inoperative. The throttle cable was examined in detail. The cable housing/actuating shaft at the carburetor end was found separated from the cable sheath, exposing the unsupported inside cable. A piece of welding rod was found bent around the housing end and taped to the sheath. The cable was removed from the aircraft and subjected to a series of operational tests. For the tests, the cable was supported by hand at each housing end and then the cockpit end was actuated, with no resistance on the carburetor end. In both push and pull directions, the carburetor end was observed to move intermittently. On some occasions, the carburetor end would move an amount corresponding to the cockpit end input; however, at other times, the carburetor end would only move slightly if at all. The pilot sustained fatal injuries in the accident and an autopsy was conducted by the Tuolumne County Sheriff/Coroner with specimens retained for toxicological analysis. The results of the toxicological tests were negative for alcohol and all screened drug substances. ## Aircraft - Registration: [N59LP](https://openairdocs.org/deregistered/N59LP-2013-03-26), registration cancelled 2013-03-26, S/N 156, built 1982 (OpenAirDocs) - Reported make and model: POWELL GLASAIR - Registry model: [Powell Lyle S JR STODDARD GLASAIR](https://openairdocs.org/model/powell-lyle-s-jr-stoddard-glasair) (registry code 05655FM) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 156 - Airframe hours: 1656 - Engines: Lycoming O-360-A1G 180 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Operator: Bobby A. Hockett - Registered owner: Bobby Hockett & Walter Maas - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 2, 1996, 1 hours before - Departed: Q68 - Airport: Q68, Pine Mountain Lake, runway 27, 3,625 × 50 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,286 total, 15 in this make and model, 6 in the last 90 days, 1 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 63 °F ## 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 19960402005749A](https://openairdocs.org/incident/19960402005749A), Apr 2, 1996: Amtr GLASAIRIII, Groveland, CA, Destroyed, 1 fatal. Aircraft crashed while returning for landing, had engine problems. ## Docket (15 files) The files NTSB released with the investigation on October 29, 1996, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=29405. 2.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 311 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438177&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Witness Statements (item 2, .PDF, 171 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438178&FileExtension=.PDF&FileName=Witness%20Statements-Redacted.PDF - FAA Wreckage Diagrams (item 3, .PDF, 92 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057112&FileExtension=.PDF&FileName=FAA%20Wreckage%20Diagrams-Master.PDF - Report from FAA Inspector (item 4, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438179&FileExtension=.PDF&FileName=Report%20from%20FAA%20Inspector-Redacted.PDF - FAA Inspectors Photo #1 (item 5, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057114&FileExtension=.PDF&FileName=FAA%20Inspectors%20Photo%20%231-Master.PDF - FAA Inspectors Photo #2 (item 6, .PDF, 49 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057115&FileExtension=.PDF&FileName=FAA%20Inspectors%20Photo%20%232-Master.PDF - FAA Inspectors Photo #3 (item 7, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057116&FileExtension=.PDF&FileName=FAA%20Inspectors%20Photo%20%233-Master.PDF - FAA Inspectors Photo #4 (item 8, .PDF, 49 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057117&FileExtension=.PDF&FileName=FAA%20Inspectors%20Photo%20%234-Master.PDF - Report Lycoming Party Participant (item 9, .PDF, 502 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057118&FileExtension=.PDF&FileName=Report%20Lycoming%20Party%20Participant-Master.PDF - Lycoming Photo #1: View of the throttle cable at the carburetor end. (item 10, .PDF, 44 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057119&FileExtension=.PDF&FileName=Lycoming%20Photo%20%231%3A%20%20View%20of%20the%20throttle%20cable%20at%20the%20carburetor%20end.-Master.PDF - Lycoming Photo #2: View of the throttle cable end. (item 11, .PDF, 31 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057120&FileExtension=.PDF&FileName=Lycoming%20Photo%20%232%3A%20%20View%20of%20the%20throttle%20cable%20end.-Master.PDF - Lycoming Photo #3: View of the welding rod and tape repair on engine end. (item 12, .PDF, 35 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40057121&FileExtension=.PDF&FileName=Lycoming%20Photo%20%233%3A%20%20View%20of%20the%20welding%20rod%20and%20tape%20repair%20on%20engine%20end.-Master.PDF - Aircraft Maintenance Records (item 13, .PDF, 318 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438180&FileExtension=.PDF&FileName=Aircraft%20Maintenance%20Records-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 14, .PDF, 221 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438181&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Toxicological Report (item 15, .PDF, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438182&FileExtension=.PDF&FileName=Toxicological%20Report-Redacted.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.