# NTSB FTW86MA058: Israel Aircraft Industries 1124A, N50SK, Redwater, TX, April 5, 1986 - Type: NTSB accident investigation - Classification: Accident · Fatal · Major investigation · Final report - Date: April 4, 1986, 19:22 local (Apr 5, 1986, 01:22 UTC) - Place: Redwater, TX - Coordinates: 33.350784, -94.249969 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.3508&lon=-94.2500&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 7 fatal - Status: Completed, report February 2, 1988 - Report: Approved by Office Director - Safety recommendations: Yes - NTSB case key (mKey): 22166 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW86MA058 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22166/pdf - Page: https://openairdocs.org/ntsb/FTW86MA058 ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, climb - to cruise - flight/nav instruments,weather radar system - failure,partial (cause) - operation with known deficiencies in equipment - continued, pilot in command (contributing factor) - In flight encounter with weather, cruise - normal - weather condition - thunderstorm (cause) - weather condition - turbulence,clear air (cause) - weather condition - gusts (cause) - weather condition - downdraft (cause) - light condition - dark night (contributing factor) - preflight briefing service - improper, atc personnel(fss) (cause) - hazardous weather advisory - not issued, atc personnel(fss) (cause) - In flight encounter with weather, cruise - normal - in-flight weather advisories - not issued, atc personnel(fss) (cause) - information unclear, atc personnel(fss) (cause) - Loss of control - in flight, cruise - normal - remedial action - attempted, pilot in command - excessive workload (task overload), pilot in command (contributing factor) - excessive workload (task overload), copilot/second pilot (contributing factor) - Loss of engine power(total) - nonmechanical, descent - uncontrolled - In flight collision with terrain/water, descent - uncontrolled ## Analysis AIRPLANE CRASHED DURING A UNCONTROLLED DESCENT, FOLLOWING A TURBULENCE UPSET AT FL370. THE UPSET OCCURRED AS A RESULT OF CLR AIR TURB ASSOCIATED WITH A VIP LVL 6 THUNDERSTORM LOCATED WITHIN 7 MILES OF THE LAST POS OF THE AIRPLANE. AFTER THE UPSET, THE AIRPLANE PENETRATED AND DESCENDED THRU THE CELL WHICH CONTAINED LIGHTNING, EXTREME TURB AND SEVERE ICING. DURING THE UPSET/DESCENT BOTH ENG'S FLAMED OUT AND THE CREW'S ATTEMPTS TO RECOVER THE AIRPLANE WERE UNSUCCESSFUL DUE TO CONDITIONS IN THE CELL. CREW RECV'D AN IMPROPER BRIEFING FROM FSS AND RPT'D THEIR RADAR WAS MALFUNCTIONING TO THE DEP CONTROLLER. SIGMET AND AWW INFO WAS NOT GIVEN DURING THE BRIEFING. AS THE AIRPLANE CAME OUT OF THE BOTTOM OF THE CELL AT 4,000', THE CREW OVERSTRESSED THE AIRPLANE CAUSING THE LFT MLG DOOR TO SEPARATE AND HIT THE LFT HORZ STAB WHICH SUBSEQUENTLY SEPARATED IN OVERLOAD. IMPACT WAS 82 DEGREES NOSE DOWN. NATURE OF THE AIRPLANE RADAR MALF COULD NOT BE DETERMINED. ## Aircraft - Registration: [N50SK](https://openairdocs.org/deregistered/N50SK-2014-12-02), registration cancelled 2014-12-02, S/N 309, built 1980 (OpenAirDocs) - Reported make and model: Israel Aircraft Industries 1124A - Registry model: [Israel Aircraft Industries 1124](https://openairdocs.org/model/israel-aircraft-industries-1124) (registry code 4500102) (OpenAirDocs) - Category: Airplane - Serial number: 309 - Airframe hours: 2745 - Engines: GARRETT TFE731-3-1G 3700 lbs thrust turbo fan - Damage: Destroyed - Fire: On-Ground - Flight: Business, Part 91 - Operator: Singer Corp. - Registered owner: Drayton Associates - Airworthiness certificate: Standard, Transport - Last inspection: Continuous airworthiness, March 7, 1986, 45 hours before - Departed: RDB, DALLAS, TX - Destination: TEB, TETERBORO, NJ - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; airline transport, commercial, flight instructor, flight engineer; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 7,353 total, 657 in this make and model, 107 in the last 90 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 60° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 4,000 ft broken - Altimeter: 29.00 inHg - Observed at: TXK, 12 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 19860404012729A](https://openairdocs.org/incident/19860404012729A), Apr 4, 1986: Israel 1124, Redwater, TX, Destroyed, 5 fatal. The pilot lost control of the aircraft in a severe thunderstorm. The horizontal stabilizers failed in overload. 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.