Midwest Airlines Flight 107
McDonnell Douglas DC9-32 · Incident: airframe, component or system failure while standing
From General Mitchell International Airport (MKE) to an unrecorded destination
Event
- NTSB case
- CHI00IA087
- 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
- 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
- Unknown
McDonnell Douglas DC9-32
- Aircraft type
- McDonnell Douglas DC9
- 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
- N203ME
- Operator
- Midwest Airlines
- Onboard fatalities
- Unknown
- Route
- From General Mitchell International Airport (MKE)To not recorded
- 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
- Standing
- 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
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Electrical system, electric wiring › Chafed
Approximate · Estimated position: the centre of Milwaukee, WI, the place the record names. Not the accident site.
NTSB narrative
During passenger boarding the flight crew was advised of smoke coming from the passenger lavatory. The flight crew instructed the flight attendants to evacuate the aircraft. All passengers and crew members exited normally. Inspection of the aircraft following the incident revealed that wiring internal to the water heater was discolored and melted adjacent to a terminal within the unit. The wire exhibited evidence of chaffing in the area next to the terminal screw. Additionally, it was found that the water heater installation was missing a grounding strap. The Federal Aviation Administration Inspector in conjunction with Midwest Express personnel determined that the missing grounding strap prevented the circuit breaker for the water heater from tripping. Subsequent to the incident, Midwest Express Airlines has inspected their DC9 aircraft to insure that the ground strap is present.
Probable cause
the chafing of the internal water heater wire. A factor was the missing ground strap.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI00IA087
- Event ID
- 20001212X20332
- Case number
- CHI00IA087
- 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. 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: 94de9f4fc1c4134d3bc6e5f98b0ef00834597cd86ac65861a5096d193b38e51d; retrieved 2026-09-18T16:49:39.850Z.
- The NTSB's operator name is blank for N203ME; the operator shown is the name the NTSB's other records give its FAA operator code, MWEA.