# NTSB LAX06CA027: Lee Kolb Mark III Classic, N515AB, Tucson, AZ, November 4, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 4, 2005, 08:30 local (15:30 UTC) - Place: Tucson, AZ - Coordinates: 32.142223, -111.174446 - Nearby events: https://openairdocs.org/map.md?lat=32.1422&lon=-111.1744&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report February 28, 2006 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 62843 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX06CA027 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62843/pdf - Page: https://openairdocs.org/ntsb/LAX06CA027 ## Probable cause the fatigue failure of the attachment that secured the horizontal stabilizer to the fuselage. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - vfr pattern - downwind - horizontal stabilizer attachment - fatigue (cause) - horizontal stabilizer attachment - failure,partial (cause) ## Analysis The airplane made a forced landing after the horizontal stabilizer attachment failed in flight. The instructional flight departed with the intention of practicing takeoffs and landings. On the downwind leg, the pilots heard a loud bang. The airplane lurched nose up, then nose down. The flight instructor took control of the aircraft and informed the tower he had a flight control problem. He was able to land the aircraft using cross control inputs. The instructor inspected the airplane and determined that the right horizontal stabilizer had separated from the fuselage due to a stainless steel "L" bracket failure. The instructor attributed the failure to a loose bolt in the "L" bracket that allowed a vibration and caused metal fatigue of the component. ## Factual narrative On November 4, 2005, about 0830 mountain standard time, an experimental Lee Kolb Mark III Classic, N515AB, suffered an in-flight right horizontal stabilizer attachment failure at Ryan Airfield Airport (RYN), Tucson, Arizona. The pilot operated the borrowed airplane under the provisions of 14 CFR Part 91. The airline transport certified flight instructor (CFI) pilot, and the student pilot undergoing instruction (PUI) were not injured; the airplane sustained substantial damage. The instructional flight departed RYN about 0830. Visual meteorological conditions prevailed, and no flight plan had been filed. In a written statement to the National Transportation Safety Board, the pilot stated that the accident occurred on the downwind to landing phase of the traffic pattern. The instructional flight departed with the intention of practicing takeoffs and landings. On the right downwind leg they heard a "loud bang." The airplane lurched nose up, then nose down. The flight instructor took control of the aircraft and informed the tower he had a "serious" control problem. The pilot was able to land the aircraft using cross control inputs. After landing, the CFI was able to taxi safely to parking. Upon inspection of the airplane by the CFI, it was determined that the right horizontal stabilizer had separated from the fuselage due to a stainless steel "L" bracket failure. In the CFI's Description of Damage to Aircraft and Other Property section of his written report, he indicated that a bolt in the "L" bracket was found slightly loose, "which allowed a slight vibration and this caused metal fatigue over its 545 [hours] of flight [time]." ADDITIONAL INFORMATION As a result of the accident, the pilot recommended to other Kolb owners (via the Kolb Kolb owner website) to replace the "L" brackets at the 250-hour inspection and to install a second set of stabilizer cables on the horizontal stabilizer. ## Aircraft - Registration: [N515AB](https://openairdocs.org/aircraft/N515AB), registered now, S/N 101553, built 2001 (OpenAirDocs) - Reported make and model: Lee Kolb Mark III Classic - Registry model: [Lee Roger MARK III CLASSIC](https://openairdocs.org/model/lee-roger-mark-iii-classic) (registry code 05619WF) (OpenAirDocs) - Registry engine: [Rotax 912ULS series](https://openairdocs.org/engine/rotax-912uls-series) (registry code 55572, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 101553 - Airframe hours: 545 - Engines: Rotax 912S 100 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Wiliam D. Fulton - Registered owner: Roger Lee & Mike Gray - Airworthiness certificate: Special, Experimental (Special) - Last inspection: 100 hour, May 1, 2005, 40 hours before - Departed: RYN, Tucson, AZ - Destination: RYN, Tucson, AZ - Airport: RYN, Ryan Field Airport, runway 6, 4,900 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 80; injuries: none; commercial, flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2; last flight review April 1, 2005; seat: left; flight hours: 18,050 total, 3 in this make and model, 17,766 as pilot in command, 130 in the last 90 days, 49 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °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 20051104031609A](https://openairdocs.org/incident/20051104031609A), Nov 4, 2005: Amtr KOLBMK3, Tucson, AZ, Substantial damage. (-23) The PIC was on the approach and the down wind leg of the ryn traffic pattern @ 800 ft AGL when the r/h horizontal stabilizer flying wire bracket/bolt… 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.