- Date
- October 8, 1992, 09:39 local (17:39 UTC)
- Place
- Anchorage, AK
- Injuries
- 26 uninjured
- Phase of flight
- Approach
- Aircraft
- N673MABoeing 737-200N680MADe Havilland DHC-8
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 8, 1993
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- Case key
- 5838
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the incident.
On this page
Probable cause
Improper ATC clearance instructions by the approach controller, resulting in a failure to insure safe separation between an airplane in visual conditions with an airplane in instrument meteorological conditions on converging courses. A factor which contributed was insufficient information provided to both pilots by the controller.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The DHC-8, N680MA, was north bound in radar control aprx 8 NM from anc intl arpt, and was provided visual separation from the B-737, N673MA, NE bound on apch to elmendorf afb. The B-737 was in clouds at the time of the advisory, and the DHC-8 mistook another B-737 for visual separation. The TCAS alerted the first B-737 pilot of close proximity of traffic approaching at at his 2 o'clock position, and he initiated a climb in IMC. A rapid descent was initiated by the DHC-8 pilot after seeing the B-737 emerging from the clouds. These evasive actions occurred approximately 20 secs prior to the crossing of the tracks of the two airplanes. ATC control of the conflicting airplanes was by the same position controller on separate frequencies. The B-737 pilot was not advised nor aware of the DHC-8 being providing visual separation from his airplane per FAA order 7110.65G until the TCAS pull-up and visual sighting of the traffic passing under and in front.
Aircraft · 2
- Registration
- N673MA
- Reported as
- Boeing 737-200
- Category
- Airplane
- Engine
- P&W JT8D-9A, turbo jet
- Damage
- No damage
- Flight
- Part 121
- Operator
- Mark Air, Inc, doing business as Mark Air
- Registered owner
- Mark Air, Inc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- AAIP · January 2, 1900
- Departed
- AKN · King Salmon, AK
- Destination
- EDF · Elmendorf Afb, AK
- Flight plan
- IFR
- Registration
- N680MA
- Reported as
- De Havilland DHC-8
- Category
- Airplane
- Engine
- turbo prop
- Damage
- No damage
- Flight
- Part 121
- Operator
- Mark Air Inc.
- Registered owner
- Mark Air Inc.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- AAIP · January 2, 1900
- Departed
- ADQ · Kodiak, AK
- Flight plan
- IFR
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot, aircraft N673MA
- Certificate
- Airline transport
- Airplane ratings
- Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Unknown
- Seat
- Left
- Role
- Pilot, aircraft N680MA
- Certificate
- Airline transport
- Airplane ratings
- Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Valid Medical--no waivers/lim.
- Seat
- Left
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 170° at 11 knots
- Lowest ceiling
- 2,800 ft broken
- Temperature
- 39 °F
- Altimeter
- 29.00 inHg
- Observed at
- ANC, 4 nm away