# NTSB CHI85IA032: McDonnell Douglas DC-10-30, N1852U, Chicago, IL, October 27, 1984

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: October 27, 1984, 13:18 local (18:18 UTC)
- Place: Chicago, IL
- Location: 41.8500° N, 87.6501° W: Placed by OpenAirDocs: center of Chicago, IL, within about 9 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.8500&lon=-87.6501&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 276 uninjured
- Status: Completed, report August 30, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 12903
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI85IA032
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12903/pdf
- Page: https://openairdocs.org/ntsb/CHI85IA032

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, climb - to cruise
  - turbine assembly,nozzle retention - failure,total (cause)
  - maintenance - improper, other maintenance personnel (cause)
  - turbine assembly,nozzle - loose
  - turbine assembly,turbine blade - failure,total
  - nacelle/pylon,fairing - separation

## Analysis

SHORTLY AFTER TAKEOFF, THE FLIGHT CREW HEARD A NOISE FROM THE RIGHT SIDE OF THE AIRCRAFT, WHICH SOUNDED LIKE AN ENGINE COMPRESSOR STALL.  THE #3 ENGINE WAS SHUT DOWN & THE CREW MADE AN UNEVENTFUL LANDING AT THE DEPARTURE AIRPORT.  PIECES OF COWLING FROM THE RIGHT ENGINE FELL IN A RESIDENTIAL AREA, BUT DID NO DAMAGE.  TEARDOWN OF THE ENGINE REVEALED THAT TURBINE BLADES ON THE FIRST STAGE LOW PRESSURE TURBINE WHEEL HAD BROKEN OFF & HAD PENETRATED THE ENGINE CASE & CORE COWL DOORS.  FURTHER INVESTIGATION REVEALED THAT 2 STUD BOLTS (SADDLE BOLTS) HAD PULLED OUT FROM STRUT BOSSES 2 & 3 IN THE TURBINE MID FRAME (TMF), WHICH PLACED AN ADDITIONAL LOAD ON STRUT BOSSES 1 & 4.  EVENTUALLY, THE 1 & 4 SADDLE BOLTS PULLED LOOSE & ALLOWED THE NOZZLE SUPPORT FLANGE TO SHIFT REARWARD.  THIS SHIFT ALLOWED THE NOZZLE SEGMENTS TO COME IN CONTACT WITH THE LOW PRESSURE TURBINE & RESULT IN THE FAILURE.  THERE WAS INDICATION THAT UNAUTHORIZED REWORK HAD BEEN ACOMPLISHED ON THE SADDLE BOLTS BEFORE OWNER (UNITED AIRLINE) HAD PURCHASED THE AIRPLANE FROM ANOTHER (LAKER) AIRLINE.

## Aircraft

- Registration: N1852U (not matched to a registry record)
- Reported make and model: McDonnell Douglas DC-10-30
- Category: Airplane
- Serial number: 47811
- Engines: GE CF6-50C2B 50400 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Registered owner: United Airlines
- Airworthiness certificate: Standard, Transport
- Destination: HNL, HONOLULU, HI
- Flight plan: IFR
- Airport: ORD, Chicago O'Hare Intl

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, unknown; seat: left

## Weather

- Conditions: Visual (VMC), Day
- Wind: 200° at 20 knots, gusting 26
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 73 °F, dew point 59 °F
- Altimeter: 29.00 inHg
- Observed at: ORD, 5 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19841027066609I](https://openairdocs.org/incident/19841027066609I), Oct 27, 1984: Doug DC1030, Chicago, IL, Substantial damage. Engine lost power, dumped fuel and landed. A row of turbine stators separated cutting aft cowl hinges.

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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