# NTSB MIA99LA045: Quicksilver MXL-2, N6153E, Humacao, PR, November 29, 1998 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: November 29, 1998, 18:00 local (22:00 UTC) - Place: Humacao, PR - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report February 16, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 45486 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA99LA045 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45486/pdf - Page: https://openairdocs.org/ntsb/MIA99LA045 ## Probable cause The pilot's use of a synthetic oil that is not recommended by the engine manufacturer when premixing his two cycle gasoline/oil fuel mixture, resulting is a total loss of engine power due to decreased lubricating properties, and the subsequent forced landing to unsuitable terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, descent - normal - fluid,oil - improper (cause) - maintenance,service of aircraft/equipment - improper, pilot in command (cause) - Forced landing, emergency descent/landing - terrain condition - none suitable ## Analysis After a flight of about 2 hours, the pilot was at about 500 feet agl, about 2 miles from his landing airport, when his two cycle engine sputtered and quit. The pilot performed a forced landing to a road in a residential area and collided with trees. Subsequent engine examination revealed sticking piston rings and piston to cylinder wall metal transfer due to lack of adequate lubrication. The pilot/operator stated he was using synthetic oil for his fuel/oil mixture. ## Factual narrative On November 29, 1998, about 1800 Atlantic standard time, a homebuilt Quicksilver MXL-2, N6153E, registered to a private individual, operating as a 14 CFR Part 91 personal flight, crashed into trees short of Humacao Municipal Airport, Puerto Rico. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage and the recreational pilot and a passenger sustained minor injuries. The flight originated from the same airport about 2 hours before the accident. According to the pilot, he had performed a gradual descent from 1,500 feet agl, to 500 feet agl, in preparation for entering the landing pattern when the engine quit, unexpectedly. All engine instrument indications were normal. The pilot was about 2 miles from the airport, and his only option appeared to be an emergency landing in a housing area. The pilot was able to land on a road, and stated that he, "could not get down fast enough even though slipping and diving. We touched down just at the end of the road and entered a yard with trees...". Collision with the two trees caused the damage and the injuries. The pilot stated he had 11 gallons of fuel on takeoff. The fuel consumption of the Rotax 503 is about 3.5 gallons per hour at normal cruise. Subsequent disassembly inspection of the two cylinder, two cycle engine, with FAA oversight, revealed that oil coking occurred on both pistons between and below the piston rings and metal transfer occurred between the upper half of the piston skirt and cylinder wall on the aft cylinder. Both sets of piston rings were stuck within their individual ring lands. According to the FAA inspector, the owner/operator was doing his own premixing of automotive gas and a synthetic oil using a mixture ratio of 100:1. According to Rotax factory personnel, synthetic oils are not recommended for premixing in their engines because of its high hydroscopic properties, especially in high humidity areas such as San Juan. Additionally, Rotax factory personnel stated a synthetic oil does not "coat" between last shutdown and first startup as well as mineral based oil. ## Aircraft - Registration: [N6153E](https://openairdocs.org/deregistered/N6153E-2002-05-04), registration cancelled 2002-05-04, S/N 180 (OpenAirDocs) - Reported make and model: QUICKSILVER MXL-2 - Registry model: [Stoughton Michael QUCKSLVR MXL II SPRT](https://openairdocs.org/model/stoughton-michael-quckslvr-mxl-ii-sprt) (registry code 05620ZN) (OpenAirDocs) - Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 180 - Airframe hours: 149 - Engines: Rotax 503 DC DCDI 52 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Michael D. Stoughton - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, July 5, 1998, 15 hours before - Departed: X63, HUMACAO MUNI, PR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 800 total, 300 in this make and model, 15 in the last 90 days, 10 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: 6,000 ft overcast - Temperature: 82 °F, dew point 75 °F - Altimeter: 29.00 inHg - Observed at: SJU, 24 nm away 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.