# NTSB ATL84IA160: Douglas DC-9-32, N923L, Mount Vernon, IL, May 4, 1984

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: May 4, 1984, 10:24 local (15:24 UTC)
- Place: Mount Vernon, IL
- Coordinates: 38.309661, -88.910362 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.3097&lon=-88.9104&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 84 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 6351
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL84IA160
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/6351/pdf
- Page: https://openairdocs.org/ntsb/ATL84IA160

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Near collision between aircraft, cruise - normal
  - crew/group coordination - improper, atc personnel(artcc) (cause)
  - crew/group coordination - improper, pilot of other aircraft (cause)
  - procedures/directives - not followed, atc personnel(artcc) (cause)
  - procedures/directives - not followed, pilot of other aircraft (cause)
  - flight advisories - not used, atc personnel(artcc) (contributing factor)
  - radar separation - not maintained, atc personnel(artcc) (cause)

## Analysis

KANSAS CITY ARTCC (ZKC) HAD CLEARED OZARK FLT 709 (A DC-9, N923L) TO CRUISE AT FL270. WHILE PROCEEDING ESE NEAR THE EDGEOF THE ZKC AREA, THE DC-9 CONVERGED ON ZORRO 11 (A FLT OF 3 F-4'S). THE F-4'S HAD BEEN CLEARED BY INDIANAPLOLIS ARTCC (ZID) TO PROCEED WESTBOUND AT FL260 TO RENDESVOUS WITH A KC-135 TANKER (SHAKE 81) TO REFUEL ON AERIAL REFUELING ROUTE AR110W. THE BEGINNING OF AR110W WAS IN THE ZID AREA; FROM THERE IT CONTINUED WESTBOUND INTO THE ZKC AREA. THE TANKER WASORBITING UNDER CONTROL OF ZKC & WAS CLEARED TO MAINTAIN BLOCK ALT FL260 TO FL290. ZID CLEARED THE F-4'S TO THE TANKER FREQ WITHOUT HANDING THEM OFF TO ZKC & WITHOUT OBTAINING APPROVAL FROM EITHER ZKC OR THE TANKER. AFTER ESTABLISHING RADIO CONTACT, THE TANKER CREW INCORRECTLY CLEARED THE F-4'S TO CLIMB TO FL270. WHEN THE ZKC CONTROLLER REALIZED THE F-4'S & DC-9 WERE CONVERGING, HE TOLD THE DC-9 CREW TO IMMEDIATELY TURN LEFT. THE DC-9 CREW SAW THE F-4'S & TOOK EVASIVEACTION. ZID HAD NOT PROPERLY COORDINATED THE F-4S' POSITION & NONE OF THE PLTS WERE INFORMED OF CONFLICTING TRAFFIC.

## Aircraft

- Registration: [N923L](https://openairdocs.org/deregistered/N923L-2013-03-18), registration cancelled 2013-03-18, S/N 47109, built 1968 (OpenAirDocs)
- Reported make and model: DOUGLAS DC-9-32
- Registry model: [Douglas DC-9-32](https://openairdocs.org/model/douglas-dc-9-32) (registry code 3022066) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT8D-1](https://openairdocs.org/engine/pratt-whitney-jt8d-1) (registry code 52044, turbo-jet) (OpenAirDocs)
- Category: Airplane
- Serial number: 47109
- Airframe hours: 43480
- Engines: P&W JT8D-9A turbo fan
- Damage: No damage
- Flight: Part 121
- Registered owner: Ozark Airlines, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, July 23, 1983, 2,098 hours before
- Departed: STL, ST. LOUIS, MO
- Destination: SDF, LOUISVILLE, KY
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; airline transport, commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 13,727 total, 8,061 in this make and model, 7,949 as pilot in command, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Lowest ceiling: none

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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