Midwest Express Airlines Flight 150
Douglas DC-9 · Accident: vortex turbulence encountered en route
From General Mitchell International Airport (MKE) to Philadelphia International Airport (PHL)
Event
- NTSB case
- NYC99LA050
- 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
- 0
- 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
Douglas DC-9
- Aircraft type
- Douglas DC-9
- 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
- N300ME
- Operator
- Midwest Express Airlines
- Onboard fatalities
- Unknown
- Route
- From General Mitchell International Airport (MKE), Milwaukee, WITo Philadelphia International Airport (PHL), Philadelphia, PA
- 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 · descent
- First occurrenceThe 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
- Vortex turbulence encountered
- 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
- Wake turbulence › Encountered
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The DC-9 departed and climbed to flight level 290. About 1 hour and 35 minutes after departure, the airplane was cleared by ATC to 17,000 feet msl. Upon receiving the clearance, the captain initiated approximately a 3,500 foot per minute descent, and slowed to 280 knots. While in the descent and passing flight level 235, the airplane encountered the wake turbulence of a cargo Boeing 747, which was 12 nautical miles ahead and also descending to 17,000 feet msl. The captain of the DC-9 pitched the airplane's nose up to exit the wake turbulence, and requested additional separation between the two airplanes from ATC. During the wake turbulence encounter, a flight attendant in the galley slipped, and seriously injured her right ankle.
Probable cause
The wake turbulence from the proceeding Boeing 747.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record NYC99LA050
- Event ID
- 20001204X00105
- Case number
- NYC99LA050
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (5)
- 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: investigation status, damage. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 08adfa0b4378719ff6c312a0b272471cc5a5c1d54a58cacba11f04e5a8618928; retrieved 2026-09-18T17:00:39.810Z.
- The NTSB's operator name is blank for N300ME; the operator shown is the name the NTSB records it doing business as.