CHI01IA016 · Boeing B-727-61
Boeing B-727-61 · Incident: airframe, component or system failure on approach
From Detroit Metropolitan Wayne County Airport (DTW) to Chicago O'Hare International Airport (ORD)
Event
- NTSB case
- CHI01IA016
- 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
- General aviation
- 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
Boeing B-727-61
- Aircraft type
- Boeing 727
- 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
- N530KF
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Detroit Metropolitan Wayne County Airport (DTW), Detroit, MITo Chicago O'Hare International Airport (ORD), Chicago, IL
- 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 91: General Aviation
- 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
- Approach
- 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
- Flight control, flap surface › Corroded
- Flight control, flap surface › Debonded
- Other maintenance personnel › Maintenance, overhaul, inadequate
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
A U. S. Marshals Service employee, who was seated on the left side, middle section of the airplane's passenger cabin, said, "I was observing the ground area looking down and aft across the wing. The wing flaps were partially deployed when I observed a large piece of the flap area to rise and leave the a/c and disappear. The flaps continued down and I could not see the particular area the piece left from, from my position any longer." On landing, it was discovered that a 6-foot long, 16-inch wide outboard section of the aft segment of the left inboard, segmented fowler flap was missing. The segment was located at a residence 2 miles west of the airport. An examination of the flap segment revealed that the anodized layer was incomplete on the segment spar and a required oxide layer was not present. The area showed corrosion and the degrading of the bond resulting in separation between the honeycomb and the aft side of the segment spar. The flap segment had been in service since its overhaul in October 1993 and had approximately 5,000 hours. Overhaul facility instructions did not specify a maximum area of the flap segment's honeycomb core that could be debonded during the overhaul. Manufacturer's repair manuals did specify a maximum size for repair of the honeycomb core in the inboard and outboard trailing edge fore flap, but none of the figures in the manual that was in effect at the time of the overhaul covered repair to the honeycomb core for the aft flap segment. A current version of the manufacturer's repair manuals specifies the maximum size for the repair of the trailing edge aft flap segment that includes the honeycomb core.
Probable cause
Inadequate overhaul of the flap segment that allowed for corrosion and debonding that resulted in the flap segment departing the airplane during the approach. Factors relating to this incident were insufficient information provided to the overhaul facility by the airplane manufacturer.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI01IA016
- Event ID
- 20001212X22115
- Case number
- CHI01IA016
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: 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: 4176c7d2b517d1dc3b63338d5a012ec7a8a32aa7eed3ff90c2808b63ce2d1560; retrieved 2026-09-22T12:22:35.593Z.