McDonnell Douglas DC-9-51 N766NC

Summary

On 14 October 1999 at about 18:55 local time, a McDonnell Douglas DC-9-51 registered N766NC was involved in an incident near Chicago, Illinois, United States. 105 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 October 1999 at 18:55

Classification

Incident

Location

Chicago, Illinois, United States

Nearest airport

Chicago Midway Airport (MDW)

Coordinates

41.7797, -87.7703

Aircraft

McDonnell Douglas DC-9-51

Registration

N766NC

Category

Airplane

Engines

2

Operator

Not recorded

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Unknown → Detroit

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

CHI00IA009

Nobody was injured.

The landing gear's wheel separation due to the improper installation of the wheel by company maintenance personnel using incomplete maintenance steps, and the maintenance steps not listed in the manufacturer's manual. Factors were the airport perimeter wall and the vehicles.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

A DC-9-51 sustained a left outboard main (#1 main) wheel and tire assembly separation on takeoff. That wheel impacted and dislodged the airport's perimeter wall and impacted a vehicle on a nearby road. The wall panels impacted another vehicle. No injuries were reported. The flight landed without incident at its intended destination. That tire assembly was found pressurized and its hubcap was found intact. Its axle nut was found intact under the hubcap. The interior portion of the #1 axle was examined and its internal threads were found intact. The anti-skid transducer adapter was found loosened inside the axle's threads and backed out 4 1/2 turns. A gap was designed to exist between the adapter and the nut. The axle nut was found to contact the adapter when the adapter was backed out to the position as found. The tire was changed on October 1, 1999. The mechanics installed the wheel in accordance with manual 32-40-1. That manual was reviewed and its steps did not caution mechanics to check for the proper depth of the adapter. DC-9-20 through 40 series airplane's anti-skid transducer assemblies were initially secured in position through safety wire. Service Bulletin (SB) 32-111 was issued to incorporate a set screw method in lieu of safety wiring the anti-skid transducer in place. This airplane's SB 32-111 modification was incorporated prior to its delivery to the airline. Subsequent to the incident, the manufacturer issued temporary service bulletins to the affected airplane's 32-40-01 maintenance manuals, cautioning mechanics to check the depth dimension of the transducer adapter with reference to the applicable technical data.

Quoted verbatim from the NTSB record.