United Air Lines Flight 1632
Boeing 737-724 · Accident: turbulence encounter en route
From George Bush Intercontinental Airport (IAH) to LaGuardia Airport (LGA)
Event
- NTSB case
- DCA12LA091
- 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
- Accident
- 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
- Instrument Meteorological Cond
Boeing 737-724
- Aircraft type
- Boeing 737
- 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
- N16709
- Operator
- United Air Lines
- Onboard fatalities
- Unknown
- Route
- From George Bush Intercontinental Airport (IAH), Houston, TXTo LaGuardia Airport (LGA), La Guardia, NY
- 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 121: Air Carrier
- 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 · climb to 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
- Turbulence encounter
- 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
- Environmental issues › Conditions/weather/phenomena
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight encountered an area of severe turbulence during the climb at about flight level 221 on departure that seriously injured two flight attendants (FA). The flight crew was aware of the forecasted convective conditions and potential for turbulence forecast along their route of flight. The captain and FAs differed in their recollection about the turbulence discussion during the pre-flight briefing. The FAs were not aware of the turbulence potential during the flight and began their service before the captain instructed them as he intended. The weather radar tilt setting of +1 degree used by the flight crew would be useful for detecting the tops of medium range and distant storms but would not be useful in detecting the rapidly developing nearby cells below and in front of the airplane. A negative tilt setting on the weather radar was recommended by the company to detect cells building in front of the airplane. As a result, the flight penetrated a rapidly developing area of "extreme" convective activity that produced severe convectively induced turbulence.
Probable cause
the flight crew's penetration of a rapidly developing thunderstorm cell in an area of forecasted convective activity. The serious injuries were the result of a misunderstanding between the captain and cabin crew regarding the potential for turbulence.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA12LA091
- Event ID
- 20120613X32202
- Case number
- DCA12LA091
- 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 2012-06-13.
- API snapshot SHA-256: dbd649390a9c5bbee9022a95c52a71c85c719135a14be73c68fe755ed5e16758; retrieved 2026-09-15T18:29:51.104Z.