# NTSB NYC99IA036: Boeing 737, New York, NY, December 8, 1998

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: December 8, 1998, 17:25 local (22:25 UTC)
- Place: New York, NY
- Coordinates: 40.749393, -73.999015 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.7494&lon=-73.9990&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 52 uninjured
- Status: Completed, report April 20, 2000
- Report: Approved by Office Director
- NTSB case key (mKey): 45471
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC99IA036
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45471/pdf
- Page: https://openairdocs.org/ntsb/NYC99IA036

## Probable cause

The Cessna pilot's incorrect visual identification of the Boeing 737's altitude, and decision to take evasive action that was not required, which resulted in the two airplanes coming within 500 feet horizontally, and 0 feet vertically of one another.

## Sequence of events

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

- Miscellaneous/other, approach
  - weather condition - rain
  - identification of aircraft visually - inaccurate, pilot in command (cause)
  - evasive maneuver - not required, pilot in command (cause)

## Analysis

The Boeing 737 was on downwind for La Guardia's runway 4, at 4,000 feet msl, when the crew caught a glimpse of three lights.  The lights were red, white, green, and aligned vertically with the red light on the bottom.  The first officer saw the other airplane, and had enough time to realize they were not going to collide, but not enough time to execute an evasive maneuver.  In addition, the airplane's traffic alert collision avoidance system went from 'TRAFFIC' to 'MONITOR VERTICAL SPEED' to 'CLEAR OF CONFLICT' in approximately 2 seconds.  The other airplane was a Cessna 172, IFR, at 5,000 feet msl.  The pilot of that airplane saw the Boeing 737 at his 12 O'clock position, and perceived it to be at the same altitude.  To avoid a perceived collision, the Cessna pilot executed a descent, and at 4,000 feet msl, the two airplanes passed 0 feet vertically and 500 feet horizontally from one another.

## Factual narrative

On December 8, 1998, about 1725 eastern standard time, a Boeing 737, C-GCPX, operated by Canadian Airlines International Ltd. as Flight 528, experienced a near midair collision while maneuvering to land at La Guardia Airport, New York, New York.  The airplane was not damaged, and the 2 flight crewmembers, 4 flight attendants, and 46 passengers were not injured.  Instrument meteorological conditions prevailed and an Instrument Flight Rules (IFR) flight plan had been filed for the scheduled passenger flight that was conducted under 14 CFR Part 129.

According to the duty chief dispatcher for Canadian Airlines, the Boeing 737 was on downwind for La Guardia's runway 4, at 4,000 feet msl, when the crew caught a glimpse of three lights.  The lights were red, white, green, and aligned vertically with the red light on the bottom.

The duty chief dispatcher added that the first officer saw the other airplane and had enough time to realize they were not going to collide, but not enough time to execute an evasive maneuver.  In addition, the airplane's traffic alert collision avoidance system went from "TRAFFIC" to "MONITOR VERTICAL SPEED" to "CLEAR OF CONFLICT" in approximately 2 seconds.

According to the Federal Aviation Administration's Preliminary Pilot Deviation Report, the other airplane was a Cessna 172, IFR, at 5,000 feet msl.  The pilot of that airplane apparently saw the Boeing 737 at his 12 O'clock position and perceived it to be at the same altitude.  To avoid a perceived collision, the Cessna pilot executed a descent, and at 4,000 feet MSL, the two airplanes passed 0 feet vertically and 500 feet horizontally from one another.

## Aircraft

- Registration: GCPX (not matched to a registry record)
- Reported make and model: Boeing 737
- Category: Airplane
- Serial number: 22341
- Engines: P&W JT8D-17 16000 lbs thrust turbo jet
- Damage: No damage
- Flight: Part 129
- Registered owner: Canadian Airlines
- Airworthiness certificate: Standard, Transport
- Departed: YYZ, TORONTO, OF
- Destination: LGA, NY
- Flight plan: IFR
- Airport: LGA, La Guardia Airport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 52; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.

## Weather

- Conditions: Instrument (IMC), Dusk
- Wind: 346° at 5 knots
- Visibility: 7 statute miles
- Lowest ceiling: 900 ft overcast
- Temperature: 45 °F, dew point 46 °F
- Altimeter: 30.00 inHg
- Observed at: LGA

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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