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Airborne Express Flight 135

13 Oct 1995 · Cedar Rapids, IA, United States

McDonnell Douglas DC-9-31 · Accident: airframe, component or system failure en route

From Des Moines International Airport (DSM) to Wilmington Airpark (ILN)

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Event

NTSB case
CHI96LA011
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

McDonnell Douglas DC-9-31

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
N945AX
Onboard fatalities
Unknown
Route
From Des Moines International Airport (DSM), Des Moines, IATo Wilmington Airpark (ILN), WILLMINGTON, OH
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
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
Substantial

Cause areas

  • Maintenance, installation › Inadequate
  • Miscellaneous, bolt/nut/fastener/clamp/spring › Not safetied
  • Thrust reverser › Failure

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

Shortly after an intermediate level-off at 13,000 feet, the crew heard a loud bang and felt the airplane shudder. They diverted to a nearby airport. During the landing roll, the engine's thrust reversers were deployed. The right engine thrust reverser deploy light illuminated. The left engine thrust reverser deploy light did not illuminate. Maintenance personnel found the left engine lower thrust reverser door had been struck repeatedly by the top reverser door. An investigation revealed broken and bent thrust reverser linkages. A pivot bolt, washers, castellated nut, and cotterpin associated with a driver linkage arm were missing. Two other company airplanes were found with a missing cotterpin from the pivot bolt. Examination of these assemblies revealed the bolt end did not protrude beyond the nut's outer edge. The result was that the cotterpin could not fit through the hole in the bolt. The manufacturer's parts manual and maintenance manual text indicated that one countersunk washer should have been below the bolt head and one flat washer under the nut. However, the corresponding illustration in the maintenance manual showed an additional washer (2 washers) under the nut.

Probable cause

inadequate installation of a thrust reverser, driver linkage arm pivot bolt and nut, which resulted in the nut and bolt becoming disconnected. A factor relating to the accident was: the manufacturer's unclear information regarding the type and number of washers to be installed on the pivot bolt assembly.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CHI96LA011
Event ID
20001207X04665
Case number
CHI96LA011
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: local date, investigation status. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 1995-10-14.
  • API snapshot SHA-256: ccb68201fb68e129cb2d03dac0a574b6bc808c71fb84c7847e6e5159c5e24163; retrieved 2026-09-18T17:57:05.942Z.