# NTSB SEA93LA148: Cessna 414A, N4735A, Seattle, WA, July 3, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 2, 1993, 18:15 local (Jul 3, 1993, 01:15 UTC) - Place: Seattle, WA - Coordinates: 47.540473, -122.309204 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.5405&lon=-122.3092&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 1, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 41728 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA93LA148 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41728/pdf - Page: https://openairdocs.org/ntsb/SEA93LA148 ## Probable cause THE DISENGAGEMENT OF THE GEAR DOWN-LOCK MECHANISM DUE TO CORROSION AND THE PILOT'S INTENTIONAL OPERATION OF THE AIRCRAFT WITH KNOWN DEFICIENCIES IN EQUIPMENT. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - roll - landing gear,gear locking mechanism - disengaged (cause) - landing gear,gear locking mechanism - corroded (contributing factor) - operation with known deficiencies in equipment - intentional, pilot in command (cause) ## Analysis UPON ARRIVAL AT HIS ORIGINAL DESTINATION, THE PILOT CYCLED THE GEAR SIX TIMES, BUT THE GREEN GEAR-DOWN LIGHT FOR THE RIGHT MAIN GEAR DID NOT ILLUMINATE. AFTRER USING THE EMERGENCY EXTENSION SYSTEM TO BLOW THE GEAR DOWN, THE RIGHT MAIN GEAR-DOWN LIGHT ILLUMINATED. AFTER LANDING, THE PILOT MADE AN INSPECTION OF THE GEAR, BUT DID NOT CONTACT HIS COMPANY MAINTENANCE PERSONAL OR USE AN EXTERNAL LOCK TO HOLD THE GEAR IN A DOWN-AND-LOCKED POSITION. HE THEN DEPARTED FOR HIS FINAL DESTINATION, LEAVING THE GEAR IN THE DOWN POSITION. DURING THE SUBSEQUENT LANDING ROLL, THE RIGHT MAIN GEAR COLLAPSED. CORROSION AND SCORING OF THE METAL WAS FOUND INSIDE THE DOWN-LOCK TUBE WERE THE TEETH OF THE DOWN-LOCK MECHANISM SLIDE INTO THE ENGAGED POSITION. ## Factual narrative On July 2, 1993, at approximately 1815 Pacific daylight time (PDT), a Cessna 414A, N4735A, experienced a main gear collapse while landing at King County International Airport/Boeing Field, Seattle, Washington. The FAA certificated airline transport pilot, who was the sole occupant of the aircraft, was not injured, but the aircraft sustained substantial damage. The flight, which departed Winthrop, Washington about 1710 PDT, was operating in visual meteorological conditions at the time of the accident. The aircraft was on an IFR flight plan, and there was no report of an ELT activation. According to the pilot, while preparing to land at Winthrop, the green gear-down light for the right main gear did not illuminate after he put the gear handle in the down position. He then cycled the gear five times, and checked the bulb itself to make sure it was good, but still did not get a green gear-down light. He then used the emergency extension system to "blow" the gear down, after which the right main gear-down light illuminated. After having someone on the ground check the gear position during a low pass, he landed with no further incident. After making a ground check of the aircraft, the pilot departed Winthrop en route to Seattle. The pilot said that during the takeoff, the gear-light holder fell out of the panel and ended up on the cabin floor. He said he did not raise the gear, and after getting the aircraft stabilized at cruise, he put the holder back in position. According to the pilot, as he was putting the holder back into position, the lights flickered and went out, followed by the loss of a number of other electrical components. He then continued on to Boeing Field and executed a normal landing. After touchdown, at a speed of about 60 to 70 knots, the right main gear collapsed. According the FAA Inspector who responded to the accident, the pilot did not attempt to contact his company maintenance personal while on the ground at Winthrop, nor did he lock the gear in the down position with an external mechanical lock prior to departure from Winthrop. Inspection of the internal down-lock mechanism showed scoring and corrosion of the metal in the area where the down-lock teeth are meant to slide into the engaged position. ## Aircraft - Registration: N4735A (not matched to a registry record) - Reported make and model: CESSNA 414A - Category: Airplane - Serial number: 414A0090 - Airframe hours: 3582 - Engines: CONTINENTAL TSIO-520-N 310 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Operator: Galvin Flying Service - Registered owner: Genka, Jon K. T. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 30, 1993, 53 hours before - Departed: S52, WINTHROP, WA - Flight plan: IFR - Airport: BFI, Boeing Field/ King County, runway 13, 10,000 × 200 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; commercial, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 7,500 total, 1,000 in this make and model, 7,350 as pilot in command, 30 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 10 knots - Visibility: 15 statute miles - Lowest ceiling: 4,000 ft broken - Temperature: 61 °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 19930702033669A](https://openairdocs.org/incident/19930702033669A), Jul 2, 1993: Cessna 414A, Seattle, WA, Substantial damage. No green light on gear extension blew gear down. Returned to base. Gear collapsed on landing. Down lock defect. 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.