# NTSB SEA94FA121: Aero Commander 500A, N601MK, Livermore, CA, May 20, 1994 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: May 19, 1994, 17:54 local (May 20, 1994, 00:54 UTC) - Place: Livermore, CA - Coordinates: 37.680828, -121.750274 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.6808&lon=-121.7503&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 4 fatal - Status: Completed, report April 7, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 41804 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA94FA121 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41804/pdf - Page: https://openairdocs.org/ntsb/SEA94FA121 ## Probable cause A FUEL SYSTEM LEAK, INADEQUATE PREFLIGHT BY THE PILOT (PIC), AND BY THE NON-FLYING PILOT/PASSENGER INTENTIONALLY ALLOWING OPERATION OF THE AIRCRAFT WITH A KNOWN DEFICIENCY (FUEL LEAK). A FACTOR RELATED TO THE ACCIDENT WAS: THE LACK OF SUITABLE TERRAIN FOR A FORCED LANDING. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, standing - engine(s) not operating - fuel system - leak (cause) - Fire, cruise - aircraft preflight - inadequate, pilot in command (cause) - operation with known deficiencies in equipment - intentional, pilot passenger (cause) - impairment(drugs), pilot passenger - Forced landing, emergency descent/landing - In flight collision with object, landing - terrain condition - none suitable (contributing factor) - object - tree(s) - object - wire,transmission ## Analysis THE AIRCRAFT HAD NOT FLOWN FOR 2 YEARS. BEFORE FLIGHT, A MECHANIC SAW EVIDENCE OF FUEL LEAKING AT DRAIN HOLES IN THE LEFT WING ROOT, JUST AFT OF THE MAIN CABIN DOOR. HE BROUGHT THIS TO THE ATTENTION OF THE PILOT-RATED PASSENGER, WHO SHORTLY THEREAFTER, DEPARTED IN THE AIRCRAFT WITH THE PILOT (PIC), THE AIRCRAFT OWNER & A PASSENGER/MECHANIC. ABOUT 14 MINUTES AFTER TAKEOFF, RADAR DATA SHOWED THE AIRCRAFT TRANSITIONING FROM A CLIMB TO A DESCENT, WHILE IN A 180 DEGREE TURN. ALSO, WITNESSES SAW SMOKE/FLAMES TRAILING FROM THE AIRCRAFT. SUBSEQUENTLY, THE AIRCRAFT IMPACTED TREES & POWER LINES, THEN IT CRASHED IN A SMALL FLAT FIELD IN HILLY TERRAIN. POST-CRASH EXAMINATION REVEALED MELTED ALUMINUM SPATTERS ON THE LEADING EDGE & UNDERSIDE OF THE LEFT HORIZONTAL STABILIZER. ALSO, 'FOCALIZED' FIRE DAMAGE WAS NOTED ON THE CABIN BEHIND THE DRAIN HOLES IN THE LEFT WING ROOT. TETRAHYDROCANNABINOL CARBOXYLIC ACID (MARIJUANA) WAS DETECTED IN THE PILOT-RATED PASSENGER'S BLOOD (0.004 UG/ML) & URINE (0.010 UG/ML). ## Factual narrative HISTORY OF FLIGHT On May 19, 1994, at 1754 hours Pacific daylight time (PDT), an Aero Commander 500A, N601MK, registered to Michele M. Mellor, and being flown by Thomas O. Lake, a commercial pilot, was destroyed during a collision with trees, power lines and terrain, six nautical miles southeast of Livermore, California. The pilot, a pilot-rated passenger occupying the front right seat, the aircraft owner, and a fourth passenger (mechanic) were fatally injured. Visual meteorological conditions existed at the time and no flight plan had been filed. The flight, which was personal in nature, was to have been conducted in accordance with 14CFR91, and originated from the Hayward Airport, Hayward, California, at 1736 hours. After departing the Hayward airport the aircraft proceeded generally south then eastbound toward Lake Del Valle. No further radio communications from the aircraft were received subsequent to its departure. However, a mode "C" 1200 transponder code was received by the Oakland Air Route Traffic Control Center. The radar data indicated that the aircraft was tracking east southeast bound when, at 1750 hours, a left 180 degree turn was executed and a transition from a climb to a descent was observed. The radius of the turn was approximately 3500 feet. The aircraft continued west northwest until 1753 when a right turn of approximately 55 degrees was executed. The last recorded radar target showed the aircraft at an elevation of 1500 feet above mean sea level (MSL) and approximately 1000 feet southeast of the crash site at 1753:57 (refer to CHART I and ATTACHMENT RD-I). Special Agent Patrick Ross, from the FBI's San Francisco office, interviewed Mr. Richard N. Garcia, a witness who observed the aircraft. Agent Ross's transcription of the interview revealed the following: Mr. Garcia was in the vicinity of Lake Del Valle approximately 1800 on the evening of the accident. He reported observing an aircraft flying over the ridge at low altitude and observed black smoke coming from the tail section. This aircraft passed directly overhead at a height of approximately 75 feet. Mr. Garcia reported that at that time he observed orange flames and thick black smoke coming from the area of the left door on the aircraft. Mr. Garcia then observed the aircraft impact trees and burst into a fireball. Mr. Joel Eckels, who was located near the southeast end of Lake Del Valle, reported observing the aircraft. He stated that he observed "identical appearing wisps of white smoke coming from both motors" and that "the white trailing behind each motor increased throughout the period (he) could see the plane" (refer to attached statement of Mr. Eckels). Mr. Randy Holliday, who was fishing at Lake Del Valle, also reported observing the aircraft. He stated that he observed the aircraft and that "there was light colored smoke coming out from behind the plane and it was dropping fast" (refer to attached statement of Mr. Holliday). PERSONNEL INFORMATION Thomas O. Lake possessed a commercial pilot certificate and was reported to be highly experienced in the Aero Commander series aircraft. No pilot log could be located, however, Mr. Lake reported a total of 23,700 hours of flight experience at the time of his most recent medical examination (12/06/93). Deryck J. Smyth possessed a private pilot certificate with only a single engine land rating. No pilot log could be located, however, Mr. Smyth reported a total of 610 hours of flight experience at the time of his most recent medical examination (05/02/94). AIRCRAFT INFORMATION The previous owner of the aircraft, Mr. Morris Kernick, stated that N601MK had "not flown since late 1991/early 1992" and that "when the aircraft was sold (to Ms. Mellor in mid 1993), he gave the new owners all the records." He also stated that "the new owners took the aircraft without his knowledge and that he was not finished with the maintenance on the aircraft." (refer to 06- 08094 RECORD OF VISIT of FAA Inspector T. Tesseny) Mr. Dennis Polito reported that he remembered "the aircraft sitting outside Mr. Kernick's hangar as far back as June" and that on the day of the accident the aircraft was taxied up to his hangar on the Hayward airport. He indicated that he was unable to fly the aircraft due to time restraints and that Mr. Lake arrived, pre-flighted the aircraft and all four occupants departed. (refer to 05-23-94 RECORD OF VISIT of FAA Inspector T. Tesseny) Mr. James McBride, a mechanic employed by Flightcraft at the Hayward airport, reported inspecting the aircraft after it was taxied up to the Flightcraft line at approximately 1400 hours. He stated that the aircraft "was in poor shape and in fact mentioned it to the people, a man and a woman, who he assumed were the owners." He stated that he "noticed a fuel leak coming from the left inboard wing root, just aft of the main cabin door." (refer to 06-09-94 RECORD OF VISIT of FAA Inspector T. Tesseny) Additionally, Special Agent Ross attended the interview of Mr. McBride by Mr. Tesseny and reported that Mr. McBride "noted that there was fuel leaking out of the drain holes in the left wing between the engine and fuselage." According to fueling records maintained by Steve Picatti at the Hayward airport, the aircraft was fueled with 75 gallons of 100 octane low lead aviation fuel on the afternoon of May 19th. The burned remains of two engine logs were recovered within the wreckage. The latest evidence of maintenance within each of the logs was an annual signed off on January 4, 1991. No other log entries were noted on the remaining blank pages following the 1991 annuals. The aircraft was equipped with a fuel system comprised of five interconnected synthetic rubber bladder type cells having a total capacity of 156 gallons, and with a single, over-wing refueling point atop the inboard right wing just aft of the leading edge. Two bladders were located in each wing. The bladders were oriented fore and aft and were situated in the wing root area between the fuselage and respective engine. The fifth bladder lay within the upper fuselage and served as a bridge between the left and right wing bladders. WRECKAGE AND IMPACT INFORMATION The aircraft crashed in a small, flat field along the north edge of Mines Road. The terrain around the accident was characterized by rapidly changing elevations. The latitude and longitude of the ground impact site was 37 degrees 36.8 minutes North and 121 degrees 41.4 minutes west respectively and the elevation of the ground impact site was approximately 800 feet MSL (refer to CHART I). The first evidence of impact was with eucalyptus trees located along the south edge of Mines Road. The tree impacts were approximately 70 feet above ground. Additionally, a power line approximately 40 feet above ground, and running parallel to the north edge of Mines Road was impacted. The aircraft impacted the ground slightly north of the power line impact and the distance from the first evidence of ground impact to the final resting place of the fuselage was 225 feet. The magnetic bearing from the tree and power line impacts, through the initial ground impact and on to the aircraft's final resting place was 340 degrees (refer to photographs 01 and 02). Several fragments including wing leading edge and right stabilizer/elevator were observed along the wreckage distribution track and displayed semi-circular impact impressions similar in diameter to that of the impacted tree trunks. The right wingtip was observed near the initial ground impact site and displayed evidence of electrical arcing and two impact depressions. The depressions were consistent with a braided wire impact and showed copper transfer. The power lines consisted of braided, copper wires (refer to photograph 03). The right wing (outboard of the right engine nacelle), including sections of flap and aileron, was observed lying on the ground near the initial ground im ## Aircraft - Registration: [N601MK](https://openairdocs.org/deregistered/N601MK-2013-06-04), registration cancelled 2013-06-04, S/N 500A-1073-47, built 1961 (OpenAirDocs) - Reported make and model: AERO COMMANDER 500A - Registry model: [Aero Commander 500-A](https://openairdocs.org/model/aero-commander-500-a) (registry code 0141104) (OpenAirDocs) - Registry engine: [Continental I0-470 series](https://openairdocs.org/engine/continental-i0-470-series) (registry code 17027, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 500A-1073 - Engines: CONTINENTAL IO-470-M 260 horsepower reciprocating - Damage: Destroyed - Fire: In-Flight - Flight: Personal, Part 91 - Operator: Mellor, Michele, M. - Registered owner: Mellor, Michelle, M. - Airworthiness certificate: Standard, Normal - Departed: HWD, HAYWARD, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 23,700 total ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 8 knots - Visibility: 25 statute miles - Lowest ceiling: 5,000 ft broken - Altimeter: 30.00 inHg - Observed at: LVK, 8 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 19940519011739A](https://openairdocs.org/incident/19940519011739A), May 19, 1994: Gulstm 500A, Livermore, CA, Destroyed, 4 fatal. Idle for two yrs. Fuel leaking into wings. Observed goind down smoke and flames. Fuel caught fire. 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.