Grumman A6E and Grumman-Schweizer G-164A mid-air collision near Steptoe, Washington, April 14, 1993
On April 14, 1993 at about 10:24 pm local time, 2 aircraft, Grumman A6E (USN) and Grumman-Schweizer G-164A (N8630H), were involved in a mid-air collision near Steptoe, Washington. 2 people were seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE INHERENT LIMITATIONS OF THE SEE-AND-AVOID CONCEPT OF SEPARATION OF AIRCRAFT OPERATING UNDER VISUAL FLIGHT RULES THAT PRECLUDED THE CREW OF THE A6E AND THE PILOT OF THE AGCAT FROM RECOGNIZING A COLLISION HAZARD AND TAKING ACTIONS TO AVOID A MIDAIR COLLISION.
THE INHERENT LIMITATIONS OF THE SEE-AND-AVOID CONCEPT OF SEPARATION OF AIRCRAFT OPERATING UNDER VISUAL FLIGHT RULES THAT PRECLUDED THE CREW OF THE A6E AND THE PILOT OF THE AGCAT FROM RECOGNIZING A COLLISION HAZARD AND TAKING ACTIONS TO AVOID A MIDAIR COLLISION.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 14, 1993 · about 10:24 pm local time · cases in 1993
- Place
- Steptoe, Washington · map
- Type
- Accident · mid-air collision
- Injuries
- 2 people were seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Grumman A6E
- Registration
- USN · registered outside the United States · serial 155665
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · military rules
- Aircraft 2
- Grumman-Schweizer G-164A
- Registration
- N8630H · no longer on the register · serial 1439
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative for the Grumman A6E final · quoted from the NTSB record
THE A6E WAS TRACKING 033 DEG LEVEL AT 200 FT AGL AT 468 KTS VFR IN PUBLISHED ROUTE VR-1354. THE AGCAT WAS TRACKING 334 DEG LEVEL AT 200 FT AGL AT 96 KTS VFR ACROSS THE ROUTE TO HIS DESTINATION SPRAY FIELD. THE TWO AIRCRAFT CONVERGED ON A 59 DEG COLLISION ANGLE WITH A CLOSURE SPEED OF 429 KTS. THE A6E NOTIFIED FSS THAT HE WAS ENTERING THE ROUTE LATE AND PROJECTED EXITING 8 MINUTES AFTER THE PUBLISHED CLOSURE OF THE ROUTE. THE AGCAT PILOT REPORTED HE WAS UNAWARE OF ANY INFORMATION/PUBLICATIONS REGARDING THE OPERATION OF MILITARY AIRCRAFT IN THE AREA. THE LOCAL FSS WAS IN THE HABIT OF REPORTING THE ROUTE 'HOT' 24 HRS A DAY RATHER THAN THE PRECISE SCHEDULE. THE CONVERGENCE ANGLE OF THE A6E WAS 111 DEG (8 O'CLOCK POSITION & BEHIND THE AGCAT'S LEFT WING). THE CONVERGENCE ANGLE OF THE AGCAT WAS 10 DEG. AT THE PROJECTED CLOSURE SPEED THE AGCAT WOULD HAVE SUBTENDED AN ANGLE OF 0.2 DEG 8.6 SECS BEFORE IMPACT; THE A6E 19.2 SECS.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Grumman-Schweizer G-164A final · quoted from the NTSB record
THE A6E WAS TRACKING 033 DEG LEVEL AT 200 FT AGL AT 468 KTS VFR IN PUBLISHED ROUTE VR-1354. THE AGCAT WAS TRACKING 334 DEG LEVEL AT 200 FT AGL AT 96 KTS VFR ACROSS THE ROUTE TO HIS DESTINATION SPRAY FIELD. THE TWO AIRCRAFT CONVERGED ON A 59 DEG COLLISION ANGLE WITH A CLOSURE SPEED OF 429 KTS. THE A6E NOTIFIED FSS THAT HE WAS ENTERING THE ROUTE LATE AND PROJECTED EXITING 8 MINUTES AFTER THE PUBLISHED CLOSURE OF THE ROUTE. THE AGCAT PILOT REPORTED HE WAS UNAWARE OF ANY INFORMATION/PUBLICATIONS REGARDING THE OPERATION OF MILITARY AIRCRAFT IN THE AREA. THE LOCAL FSS WAS IN THE HABIT OF REPORTING THE ROUTE 'HOT' 24 HRS A DAY RATHER THAN THE PRECISE SCHEDULE. THE CONVERGENCE ANGLE OF THE A6E WAS 111 DEG (8 O'CLOCK POSITION & BEHIND THE AGCAT'S LEFT WING). THE CONVERGENCE ANGLE OF THE AGCAT WAS 10 DEG. AT THE PROJECTED CLOSURE SPEED THE AGCAT WOULD HAVE SUBTENDED AN ANGLE OF 0.2 DEG 8.6 SECS BEFORE IMPACT; THE A6E 19.2 SECS.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Grumman A6E from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot, military
- Ratings: multi-engine land; instrument: airplane
- Flight time: 2,814 hours in all; 201 in this make and model; 93 in the last 90 days; 26 in the last 30 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 4,784 hours
- Last inspection: continuous airworthiness programme, November 28, 1992; 131 hours since
- Maximum gross weight: 60,400 lb
- Seats: 2
- Landing gear: retractable
- Engine: P&W J52P-8B (turbojet); 0 hours total
The flight
- Departed from: NUW Nas Whidbey Is WA at 9:40 pm
- Destination: NUW
- Flight plan: IFR
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: broken clouds at 2,500 ft; not recorded at 2,500 ft
- Temperature: 45°F (7°C), dew point 37°F (3°C)
- Altimeter: 30.00 inHg
- Observation at 9:56 pm from PUW, 18 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 1 |
The factual record for the Grumman-Schweizer G-164A from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 2,231 hours in all; 1,460 in this make and model; 50 in the last 90 days; 50 in the last 30 days; 2,200 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 5,014 hours
- Last inspection: annual inspection, February 4, 1993; 94 hours since
- Maximum gross weight: 5,391 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: 0WA0 Colfax WA at 10:20 pm
- Destination: 0WA0
- Flight plan: none
- Runway 0
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under USN the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- Grumman 443 aircraft on the register
- N8630H: not on the register today · the record of its deregistration
- Engine: P&W J52P-8B 6 aircraft carry this series today · as the NTSB recorded it
- Engine: P&W R-1340 1,229 aircraft carry this series today · as the NTSB recorded it
- Whidbey Island Naval Air Station (Ault Field) · departed from
- Streamline Heliport · departed from
- Accidents and incidents in Washington 2,713 since 1982 · 361 in the last ten years
- Washington 10,664 aircraft registered
- Other NTSB records under USN 4 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/SEA93FA094.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.