TAM Flight 8091
Airbus A330 200 · Incident: flight instrument malfunction/failure en route
From Miami International Airport (KMIA) to SGRU · Sao Paulo
Event
- NTSB case
- DCA09IA055
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Incident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Airbus A330 200
- Aircraft type
- Airbus A330
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- PT-MVB
- Operator
- TAM
- Onboard fatalities
- Unknown
- Route
- From Miami International Airport (KMIA), Miami, FLTo SGRU · Sao Paulo
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 129: Foreign
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Flight instrument malfunction/failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Aircraft › Aircraft systems
Not plotted · Location withheld: coordinates are missing, conflicting, invalid, or have no accepted acquisition method. No substitute location has been invented.
NTSB narrative
On May 21, 2009, at 2147 EDT, an Airbus A330-200, Brazilian registration PT-MVB, operated by TAM Airlines as flight 8091 from Miami International Airport, Florida, to Sao Paulo Guarulhos International Airport, Brazil, experienced a loss of primary speed and altitude information while in cruise flight at FL370. Initial reports indicated that the flight crew noted an abrupt drop in outside air temperature and observed St. Elmo's Fire, followed by the loss of the Air Data Reference System, disconnections of autopilot and autothrust, and loss of primary airspeed and altitude. The flight crew continued using backup instruments, and after approximately 5 minutes, primary data was restored. The airplane remained in alternate flight law and displayed a rudder travel limit flag. The crew determined they could not restore normal law and continued the flight under the appropriate procedures. The flight landed at Sao Paulo with no further incident and there were no injuries or damage.
With the concurrence of the Brazilian Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA), the NTSB initiated an incident investigation into this event.
The final report for this incident was combined with and can be found under NTSB investigation number, DCA09IA064.
Probable cause
The final report for this incident was combined with and can be found under NTSB Investigation number, DCA09IA064.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA09IA055
- Event ID
- 20090624X02042
- Case number
- DCA09IA055
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status, damage. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2009-05-22.
- API snapshot SHA-256: 61aa0b6c545d2de233c9101a2eaff7cf5d92a80fbbe1bc555b4ae715a0c712a1; retrieved 2026-09-15T11:33:52.736Z.