# NTSB FTW04IA128: Lockheed 1329-23E, N57NR, Houston, TX, May 15, 2004 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: May 15, 2004, 13:50 local (18:50 UTC) - Place: Houston, TX - Coordinates: 29.640556, -95.273887 - Nearby events: https://openairdocs.org/map.md?lat=29.6406&lon=-95.2739&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report October 28, 2004 - Report: Approved by Office Director - Parties: Flight Standards District Office, Lockhead Martin - NTSB case key (mKey): 59223 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW04IA128 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59223/pdf - Page: https://openairdocs.org/ntsb/FTW04IA128 ## Probable cause The fatigue failure of the inboard left wing actuator fitting. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - faf/outer marker to threshold (ifr) - flight control,flap - separation (cause) - flight control,flap attachment - failure,total (cause) - flight control,flap attachment - fatigue (cause) ## Analysis The 12,500-hour pilot reported that during final approach to the airport, the flaps were extended to the full-down position. Subsequently, the airplane decelerated and rolled uncontrollably to the left. The pilot regained control of the airplane and landed without incident. A post-flight inspection of the airplane by the crewmembers revealed that the left inboard flap had separated and the attach bolts were still in the flap attach brackets. Examination of the left inboard and outboard flap actuator fittings (parts number JW121-8L and JW121-6R) revealed visible evidence of fatigue and corrosion on the surface of the inboard fitting. ## Factual narrative On May 15, 2004, approximately 1350 central daylight time, a Lockheed 1329-23E turbojet airplane, N57NR, sustained minor damage following an in-flight separation of the left flap assembly while on final approach to the William P. Hobby Airport (HOU), Houston, Texas. The airplane was registered to and operated by Aircraft Trading Center Incorporated, of Tequesta, Florida. The two airline transport pilots and two passengers were not injured. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 91 business flight. The cross-country flight originated from the Corpus Christi International Airport (CRP), near Corpus Christi, Texas, approximately 1315, destined for HOU. According to the 12,500-hour pilot, as the flaps were extended to the full flaps position on final approach to Runway 4, the airplane decelerated and rolled uncontrollably to the left. The pilot stated that he regained control of the airplane by "accelerating to approximately 165-170 knots and holding right roll control." The aircraft landed without further incident. A post-flight inspection of the airplane by the crewmembers revealed that the left inboard flap had separated and the attach bolts were still in the flap attach brackets. The pilot added that the airplane had accumulated approximately 13,534.8 flight hours and 11,500 cycles. A witness near the airport observed the flap separate from the airplane after it crossed the outer marker on final approach to Runway 4. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed dents on the aft end of the left fuel tank, and dents and a hole to the engine cowling. The inboard and outboard flap actuator fittings (parts number JW121-8L and JW121-6R) were removed and sent to the Office of Research and Engineering, Materials Laboratory Division in Washington, D.C. for examination. The flap actuator fittings were examined at the NTSB Office of Research and Engineering, Materials Laboratory Division on July 16, 2004. Examination of the inboard flap actuator fitting revealed two separate regions of fatigue fractures on both sides of a manufactured hole. Each fatigue region displayed two areas with different types of fatigue cracking characteristics. Approximately one half of each fatigue region close to the origin area displayed a river pattern that radiated out from the fatigue origin areas near the corner between the hole and exterior surface. The remainder of the fatigue regions displayed a distinct banded appearance, consistent with rapid crack propagation and high stress fatigue cracking in aluminum alloys. The areas outside of the fatigue regions were consistent with overload. Areas of pitting and exfoliation, consistent with corrosion, were observed on the surface of the inboard fitting below the areas of the fatigue fractures. The outboard actuator fitting displayed fractures consistent with overload with no evidence of fatigue. ## Aircraft - Registration: N57NR (not matched to a registry record) - Reported make and model: Lockheed 1329-23E - Category: Airplane - Serial number: 5123 - Airframe hours: 13534.8 - Engines: Garrett 731-3 3700 lbs thrust turbo fan - Damage: Minor damage - Flight: Business, Part 91 - Registered owner: Aircraft Trading Center, Incorporated - Airworthiness certificate: Standard, Normal - Last inspection: Condition, April 1, 2004 - Departed: CRP, Corpus Christi, TX - Destination: HOU, Houston, TX - Flight plan: IFR - Airport: HOU, William P. Hobby, runway 4, 7,602 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airline transport; airplane ratings: multi-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; flight hours: 12,600 total, 1,200 in this make and model, 11,000 as pilot in command, 60 in the last 90 days, 20 in the last 30 days, 5 in the last 24 hours - Co-pilot; age 45; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; medical: class 2, without waivers/limitations; last flight review August 1, 2003; seat: right; flight hours: 8,000 total, 6,000 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 50° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 81 °F, dew point 68 °F - Altimeter: 30.09 inHg - Observed at: HOU ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20040515009459I](https://openairdocs.org/incident/20040515009459I), May 15, 2004: Lkheed 132923E, Houston, TX, Minor damage. (-23) On 15 may 2004, at 1350 local time a Lockheed 1329-23E jet star 731 aircraft registered as N57NR operating on 14 CFR 91 flight landed at the Houston… 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.