# NTSB CHI93IA110: Fokker 100, N895US, Chicago, IL, March 13, 1993

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: March 13, 1993, 16:27 local (22:27 UTC)
- Place: Chicago, IL
- Location: 41.9769° N, 87.9081° W: Placed by OpenAirDocs at CHICAGO O'HARE INTL (ORD), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=41.9769&lon=-87.9081&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 103 uninjured
- Status: Completed, report May 10, 1994
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 15595
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI93IA110
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15595/pdf
- Page: https://openairdocs.org/ntsb/CHI93IA110

## Probable cause

FAILURE OF THE COMPANY STATION MANAGER TO FOLLOW PROPER DISPATCH PROCEDURES, AND ICE ACCUMULATION ON THE NOSE GEAR LOCKING MECHANISM.  FACTORS RELATED TO THE INCIDENT WERE: WET SNOW (SLUSH) ON THE RUNWAY AT THE DEPARTURE AIRPORT, AND INADEQUATE DESIGN WHICH ALLOWED ICE TO RENDER THE NOSE GEAR DOWNLOCK SYSTEM INOPERATIVE.

## Sequence of events

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

- Nose gear collapsed, landing - roll
  - airport facilities,runway/landing area condition - slush covered (contributing factor)
  - dispatch procedures - not followed, company/operator management (cause)
  - landing gear,gear locking mechanism - frozen (cause)
  - gear down and locked - not possible, pilot in command
  - acft/equip,inadequate design, manufacturer (contributing factor)
- Airframe/component/system failure/malfunction, landing - roll
  - landing gear,normal brake system - frozen
  - landing gear,tire - failure,total

## Analysis

DOWN & LOCKED INDICATION OF NOSE GEAR WAS NOT ACHIEVED FOR LANDING.  CREW RECYCLED GEAR, USED ALTERNATE GEAR EXTENSION SYSTEM & MADE A FLY-BY.  AFTER BEING TOLD GEAR APPEARED TO BE EXTENDED, CREW LANDED, BUT NOSE GEAR COLLAPSED AT END OF LANDING ROLL.  RIGHT MAIN OUTBOARD TIRE ALSO BLEW-OUT DURING LANDING DUE TO FROZEN BRAKE.  INVESTIGATION REVEALED NOSE- WHEEL WELL WAS SUSCEPTIBLE TO ICE CONTAMINATION.  NOSE GEAR DOWN LOCK PLUNGER WAS FROZEN & WOULD NOT EXTEND TO DOWN & LOCKED POSITION. AT DEPARTURE AIRPORT, SLUSH HAD ACCUMULATED ON NOSE GEAR DOWN LOCK & FROZE. USE OF ALTERNATE EXTENSION SYSTEM WOULD HAVE DUMPED THE 500 PSI HYDRAULIC PRESSURE THAT NORMALLY ASSISTED IN HOLDING GEAR IN EXTENDED POSITION. USAIR PROCEDURES STATED THAT TAKEOFF SHOULD NOT BE MADE IF SLUSH OR WET SNOW IN EXCESS OF 1/2 INCH COVERED RUNWAY. AT LEAST 1 INCH OF WET SNOW & SLUSH WAS REPORTED ON DEPARTURE RUNWAY, 22 MINUTES BEFORE DEPARTURE; HOWEVER, ACTING STATION MANAGER DID NOT FOLLOW USAIR PROCEDURES THAT REQUIRED REPORTING THIS TO DISPATCHER & CAPTAIN OF FLIGHT.

## Aircraft

- Registration: [N895US](https://openairdocs.org/deregistered/N895US-2007-09-27), registration cancelled 2007-09-27, S/N 11380, built 1992 (OpenAirDocs)
- Reported make and model: FOKKER 100
- Registry model: [Fokker F.28 MK 0100](https://openairdocs.org/model/fokker-f-28-mk-0100) (registry code 4990807) (OpenAirDocs)
- Registry engine: [Rolls-Royce TAY-650-15](https://openairdocs.org/engine/rolls-royce-tay-650-15) (registry code 54557, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 11380
- Airframe hours: 2293
- Engines: Rolls-Royce TAY650-15 15100 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Operator: Usair, doing business as Usair
- Registered owner: Wilmington Trust Company
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, March 13, 1993
- Departed: CLT, CHARLOTTE, NC
- Destination: ORD
- Flight plan: IFR
- Airport: ORD, O'Hare Int'L, runway 4R, 8,071 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 20 knots
- Visibility: 12 statute miles
- Lowest ceiling: none
- Temperature: 19 °F, dew point 3 °F
- Altimeter: 30.00 inHg
- Observed at: ORD, 1 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 19930313007309I](https://openairdocs.org/incident/19930313007309I), Mar 13, 1993: Fokker F28MK0100, Chicago, IL, Minor damage. Unable to lock nose gear down. Nose gear collapsed on rollout. Ice packed around springloaded downlock plunger.

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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