# Accident 19991112031749A: Amrgen AG5B, Van Nuys, CA, November 12, 1999 - Type: FAA accident report (Accident/Incident Data System), as reported - Date: November 12, 1999, 17:38 local time - Place: Van Nuys, CA - Airport: Van Nuys Airport - Damage: Substantial damage - Phase of flight: Final Approach - Operating rules: Air taxi and commuter (Part 135) - Operator: DS6A - Location: 34.1906° N, 118.4910° W: From the FAA, an estimate near the named town, within about 3 miles - Nearby events: https://openairdocs.org/map.md?lat=34.1906&lon=-118.4910&mi=10 - Aircraft: N1195L, registered now (https://openairdocs.org/aircraft/N1195L) (OpenAirDocs) - Registry model: American General Acft AG5B (registry code 3990100, https://openairdocs.org/model/american-general-acft-ag5b) (OpenAirDocs) - Registry engine: Lycoming O&VO-360 series (registry code 41514, https://openairdocs.org/engine/lycoming-o-vo-360-series) (OpenAirDocs) - Reported make and model: AMRGEN AG5B - Reported engine: LYC O360A4K - People aboard: 3 - Fatal injuries: 0 - Pilot flight hours: 6,068 total, 200 in this make and model, 30 in the last 90 days - NTSB investigation: [NTSB LAX00LA035](https://openairdocs.org/ntsb/LAX00LA035) (OpenAirDocs) - FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/) - Page: https://openairdocs.org/incident/19991112031749A ## Narrative As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^. (.19) ON NOVEMBER 12, 1999, AT 1730 HOURS PACIFIC STANDARD TIME, AN AMERICAN GENERAL AG5B, N1195L WAS SUBSTANTIALLY DAMAGED BY AN ENCOUNTER WITH IN-FLIGHT TURBULENCE WHILE ON DOWNWIND LEG FOR LANDING AT THE VAN NUYS, CALIFORNIA, MUNICIPAL AIRPORT. THE AIRLINE TRANSPORT PILOT AND TWO PASSENGERS WERE NOT INJURED. VISUAL METEOROLOGICAL CONDITIONS PREVAILED FOR THE LOCAL AREA SIGHTSEEING FLIGHT, WHICH WAS OPERATED BY D&S AVIATION UNDER THE PROVISIONS OF 14 CFR PART 135. THE FLIGHT DEPARTED FROM VAN NUYS ABOUT 1545 AND NO FLIGHT PLAN WAS FILED. THE SAFETY BOARD INVESTIGATOR EXAMINED THE AIRCRAFT ON NOVEMBER 16, 1999. EACH WING IS ASSEMBLED IN THREE SECTIONS WHICH ARE SPLICED TOGETHER AND THE TIP SECTION OF THE LEFT WING, OUTBOARD OF THE SECOND SPLICE, WAS DEFORMED UPWARD ABOUT 5 DEGREES WITH RESPECT TO THE INBOARD SECTION OF THE WING. THE UPPER WING SKIN EXHIBITED COMPRESSION BUCKLING. THE BUCKLING WAS SUBSTANTIAL ON THE OUTBOARD WING SECTION AND MODEST ON THE UPPER WING SKIN INBOARD OF THE TIP SPLICE. THE RIGHT WING EXHIBITED MODEST COMPRESSION BUCKLING OVER ITS ENTIRE SPAN BUT WAS NOT VISIBLY DEFORMED. THERE WAS NO VISIBLE DAMAGE TO THE FUSELAGE, EMPENNAGE, OR LANDING GEAR. THE MASS BALANCE WEIGHTS ON BOTH AILERONS WERE ABSENT. THE STEEL TUBES SUPPORTING THE MASS BALANCES SEPARATED IMMEDIATELY FORWARD OF THE WELD ATTACHMENT TO THE AILERON TORQUE TUBE IN THE VICINITY OF THE HEAT EFFECTED REGION OF THE WELD. BOTH FAILURES EXHIBITED A SHEAR LIP ON THE TOP PORTION AND DOWNWARD BENDING ON THE BOTTOM PORTION. THERE WAS NO DAMAGE TO CONTROL STOPS OR EVIDENCE OF OVER-TRAVEL. THE PILOT REPORTED THAT THE FLIGHT WAS AN EVENING SCENIC FLIGHT OF THE SAN FERNANDO VALLEY AREA. AS THE FLIGHT WAS RETURNING TO LAND, HE ENTERED ON LEFT DOWNWIND FOR LANDING ON RUNWAY 16L. THE DOWNWIND LEG WAS FLOWN SLIGHTLY EAST OF THE 405 (SAN DIEGO) FREEWAY AT 1800 FEET MSL AND APPROXIMATELY 115 KNOTS IAS WITH FLAPS UP. AS THEY WERE ABEAM THE CONTROL TOWER ON DOWNWIND (MIDFIELD), THERE WAS AN INSTANTANEOUS JOLT OF SUDDEN SEVERE TURBULENCE THAT ENDED BEFORE HE COULD TAKE ANY ACTION. HIS LEFT HAND WAS ON THE FLIGHT CONTROLS AND HIS RIGHT HAND WAS ON THE THROTTLE. THE FLIGHT CONTROL IN HIS LEFT HAND FELT "LIKE THE HANDLE OF A SLEDGE HAMMER WHEN YOU STRIKE A STEEL PIPE." (-23)N1195L WAS ON A SIGHT-SEEING CHARTER TRIP WITH TWO PASSENGERS OVER THE LOS ANGELES AREA. AFTER AN UNEVENTFUL FLIGHT, N1195L WAS ON DOWN WIND TO RUNWAY 16L AT VNY WHEN IT EXPERIENCED A VERY HARD MOMENTARY JOLT OR BUMP APPROX. OVER THE GEOGRAPHIC LOCATION OF SHERMAN WAY AND SEPULVEDA BLVD. THE PILOT REPORTED THAT IT LASTED ONLY A SECOND AND IMMEDIATELY AFTER HE NOTICED WRINKLES IN THE TOP SKIN OF THE LEFT WING AND THE AILERON CONTROLS WERE STIFFER BUT HE COULD CONTROL THE PLANE WITHOUT ANY PROBLEMS. HE LANDED WITHOUT FURTHER INCIDENT. AFTER LANDING IT WAS DISCOVERED THAT THE LEFT WING WAS BENT UP A FEW DEGREES FROM THE OUTER WING PANEL (ABOUT 2/3 OF THE WAY TO THE TIP) AND BOTH OF THE AILERON BALANCE WEIGHTS WERE MSSING. THERE WERE NO SCRATCHES OR DENTS IN THE WING THAT WOULD HAVE INDICATED THAT SOMETHING CAME IN CONTACT WITH N1195L. TWO VNY FSDO AIRWORTHINESS INSPECTORS WERE CALLED TO AN APARTMENT BUILDING ON 11-16-99 IN RESPONSE TO A REPORT OF AN AIRCRAFT PART FALLING THROUGH THE CEILING. THE APARTMENT MANAGER LED THEM TO A VACANT APARTMENT AND SHOWED THEM A HOLE IN THE CEILING OF THE BEDROOM AND ONE OF THE AILERON BALANCE WEIGHTS FROM N1195L ON THE FLOOR. THIS APARTMENT BUILDING IS LOCATED ABOUT 75 YARDS FROM THE NORTHWEST CORNER OF SHERMAN WAY AND SEPULVEDA BLVD. (.4)ON NOVEMBER 12, 1999, AT 1738 HOURS PACIFIC STANDARD TIME, AN AMERICAN GENERAL AG5B, N1195L, WAS SUBSTANTIALLY DAMAGED BY AN ENCOUNTER WITH IN-FLIGHT TURBULENCE WHILE ON DOWNWIND LEG FOR LANDING AT THE VAN NUYS, CALIFORNIA, MUNICIPAL AIRPORT. THE AIRLINE TRANSPORT PILOT AND TWO PASSENGERS WERE NOT INJURED. VISUAL METEOROLOGICAL CONDITIONS PREVAILED FOR THE LOCAL AREA SIGHTSEEING FLIGHT, WHICH WAS OPERATED BY D&S AVIATION UNDER THE PROVISIONS OF 14 CFR PART 135. THE FLIGHT DEPARTED FROM VAN NUYS ABOUT 1645, AND NO FLIGHT PLAN WAS FILED. THE PILOT REPORTED THAT THE FLIGHT WAS AN EVENING SCENIC FLIGHT OF THE LOS ANGELES AREA. IT WAS DARK WHEN THE FLIGHT RETURNED TO LAND AND ENTERED ON LEFT DOWNWIND FOR LANDING ON RUNWAY 16L (NORTHBOUND). THE DOWNWIND LEG WAS FLOWN EAST OF THE 405 (SAN DIEGO) FREEWAY AND WEST OF SEPULVEDA BOULEVARD AT 1800 FEET MSL, AND APPROXIMATELY 115 KNOTS IAS WITH FLAPS UP. AS THEY WERE ABEAM THE CONTROL TOWER ON DOWNWIND (MIDFIELD), THERE WAS AN INSTANTANEOUS JOLT OF SUDDEN SEVERE TURBULENCE THAT ENDED BEFORE HE COULD TAKE ANY ACTION. HIS LEFT HAND WAS ON THE FLIGHT CONTROLS AND HIS RIGHT HAND WAS ON THE THROTTLE. THE PILOT SAID THE FLIGHT CONTROL IN HIS LEFT HAND FELT "LIKE THE HANDLE OF A SLEDGE HAMMER WHEN YOU STRIKE A STEEL PIPE." THE PASSENGER, WHO WAS NOT A PILOT, REPORTED THAT THEY TOOK OFF ABOUT 1645 AND FLEW FOR ABOUT AN HOUR. AS THEY WERE RETURNING TO LAND AND WERE HALFWAY DOWN THE AIRPORT ON THE RIGHT SIDE TO LAND (THE PASSENGER'S DESCRIPTION), THEY FLEW THROUGH ONE HARD BUMP. IT WAS "SO FAST, LIKE AN AIR POCKET." IT FELT LIKE THEY DROPPED 10 FEET AND STOPPED; THEN THE TURBULENCE WAS GONE AND THE LANDING ROUTINE. HE FELT THAT THE SPEED WAS NORMAL, THERE WAS NO SHRIEKING OR WIND NOISE, AND THE PILOT MADE NO CONTROL INPUT BEFORE OR AFTER THE TURBULENCE. THE PILOT ESTIMATED THE OPERATING WEIGHT OF THE AIRCRAFT WAS 2,121 POUNDS. THE CERTIFICATED MANEUVERING SPEED (VA) IS 113 KNOTS IAS AT 2,400 POUNDS. ONE OF THE AILERON MASS BALANCE WEIGHTS WAS LOCATED ON NOVEMBER 16, 1999, IN THE BEDROOM OF AN UNOCCUPIED APARTMENT WHERE IT HAD PENETRATED THE ROOF AND CEILING. THE APARTMENT IS LOCATED BENEATH THE DOWNWIND LEG FLIGHT PATH ON THE EAST SIDE OF THE AIRPORT APPROXIMATELY MIDFIELD. ACCORDING TO A VAN NUYS FLIGHT STANDARDS DISTRICT OFFICE INSPECTOR, THE LOCATION WAS 50 YARDS NORTH OF SHERMAN WAY (AN EAST-WEST STREET WHICH BISECTS THE AIRPORT), AND 150 YARDS WEST OF SEPULVEDA BOULEVARD (A NORTH-SOUTH STREET WHICH IS APPROXIMATELY UNDER THE DOWNWIND LEG). THE BURBANK-GLENDALE-PASADENA (BURBANK) AIRPORT, AT BURBANK, CALIFORNIA, IS LOCATED 6 MILES EAST OF THE VAN NUYS AIRPORT, AND THE INSTRUMENT LANDING SYSTEM (ILS) FINAL APPROACH COURSE TO RUNWAY 8 PASSES OVER THE MIDFIELD OF VAN NUYS AIRPORT AT GLIDE SLOPE ALTITUDE OF 2,752 FEET (MSL). DATA OBTAINED FROM THE VAN NUYS AND BURBANK AIRPORT NOISE ABATEMENT OFFICES SHOWED THAT A HEAVY FEDERAL EXPRESS AIRBUS A-300-B4-600, FLIGHT 2216, PASSED OVERHEAD THE VAN NUYS AIRPORT AT 1735:54, AT 2,675 FEET, AND PASSED OVER THE GRUMMAN'S DOWNWIND FLIGHT PATH LOCATION EAST OF THE 405 FREEWAY AT 1736:33, AT 2297 FEET (MSL). THE SAME DATA SHOWS AN AIRCRAFT ON A VFR TRANSPONDER CODE FLYING NORTHBOUND AND CROSSING UNDER THE AIRBUS' FLIGHT PATH AT 1738:56, AT 1,800 FEET MSL. THE INTERSECTION OF THE TWO FLIGHT PATHS IS APPROXIMATELY THE LOCATION WHERE THE AILERON MASS BALANCE WAS LATER LOCATED. A RECORDING OF VAN NUYS AIR TRAFFIC CONTROL TOWER COMMUNICATIONS ON THE FREQUENCY USED TO CONTROL TRAFFIC ON THE EAST SIDE OF THE AIRPORT REVEALED THAT THE TOWER BROADCAST A WAKE TURBULENCE CAUTIONARY ADVISORY TO ALL AIRCRAFT. THE ACCIDENT AIRCRAFT MADE INITIAL CONTACT WITH THE TOWER APPROXIMATELY 30 SECONDS LATER. THE WAKE TURBULENCE ADVISORY WAS NOT REPEATED. THE SAFETY BOARD INVESTIGATOR EXAMINED THE AIRCRAFT ON NOVEMBER 16, 1999. EACH WING IS ASSEMBLED IN THREE SECTIONS, WHICH ARE SPLICED TOGETHER. THE TIP SECTION OF THE LEFT WING, OUTBOARD OF THE SECOND SPLICE, WAS DEFORMED UPWARD ABOUT 5 DEGREES WITH RESPECT TO THE INBOARD SECTION OF THE WING. THE UPPER WING SKIN EXHIBITED COMPRESSION BUCKLING. IN COMPARING THE TWO DAMAGE AREAS, THE BUCKLING WAS SUBSTANTIAL ON THE OUTBOARD WING SECTION AND MODEST ON THE UPPER WING SKIN INBOARD OF THE TIP SPLICE. THE RIGHT WING EXHIBITED MODEST COMPRESSION BUCKLING OVER ITS ENTIRE SPAN BUT WAS NOT VISIBLY DEFORMED. THERE WAS NO VISIBLE DAMAGE TO THE FUSELAGE, EMPENNAGE, OR LANDING GEAR. THE MASS BALANCE WEIGHTS ON BOTH AILERONS WERE ABSENT. THE STEEL TUBES SUPPORTING THE MASS BALANCES SEPARATED IMMEDIATELY FORWARD OF THE WELD ATTACHMENT TO THE AILERON TORQUE TUBE IN THE VICINITY OF THE HEAT AFFECTED REGION OF THE WELD. BOTH FAILURES EXHIBITED A SHEAR LIP ON THE TOP PORTION AND DOWNWARD BENDING ON THE BOTTOM PORTION. THERE WAS NO DAMAGE TO CONTROL STOPS OR EVIDENCE OF OVER-TRAVEL. ## The NTSB's investigation of this event (1) 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. - [NTSB LAX00LA035](https://openairdocs.org/ntsb/LAX00LA035), Nov 13, 1999: American General AG5B (N1195L), Van Nuys, CA, substantial damage. Probable cause: The pilot's encounter with unknown and unanticipated wake turbulence from a heavy transport aircraft, which was landing at another airport. A factor in the accident was the tower controller's failure… From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record. --- 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.