Boeing VC-137B-BN and Mooney M20C incident near Seattle, Washington, October 18, 1984
On October 18, 1984 at about 9:45 pm local time, 2 aircraft, Boeing VC-137B-BN (USAF) and Mooney M20C (N6507U), were involved in the same incident near Seattle, Washington. No one was hurt; 50 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this incident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 18, 1984 · about 9:45 pm local time
- Place
- Seattle, Washington · map
- Type
- Incident
- Injuries
- No one was hurt; 50 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Boeing VC-137B-BN
- Registration
- USAF · no longer on the register · serial 17925
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
- Aircraft 2
- Mooney M20C · all M20Cs on the register
- Registration
- N6507U · registry record
- Damage
- Not recorded
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative for the Boeing VC-137B-BN final · quoted from the NTSB record
DURING ARRIVAL, A BOEING VC-137B-BN, USAF #58-6970, OPERATING AS AIR FORCE 2 (AF-2), WAS CLEARED FOR A LOCALIZER BACK- COURSE APCH. AT 1442:49, TRACON ADVISED AF-2 OF TRAFFIC AT ITS 10 O'CLOCK POSITION AT 2 MI, ALT UNKN. AT 1443:11, TRACON ADVISED AF-2 THE TRAFFIC HAD MOVED TO ITS 11 O-CLOCK POSITION AT 1-1/2 MI. AF-2 ACKNOWLEDGED BOTH TRANSMISSIONS. AT 1443:29, AF-2 ADVISED THAT THE FLT WAS CHANGING ITS FREQ TO BOEING TOWER. SHORTLY THEREAFTER, THE ACFT CMDR OF AF-2, SEATED IN THE RIGHT, SAW THE TRAFFIC, A MOONEY M20C, N6507U, ON A COLLISION COURSE. HE TOOK CONTROL & INITIATED EVASIVE ACTION. THE PLT OF N6507U WAS CRUISING AT 2,500 FT OUTSIDE THE SEATTLE TCA & DID NOT SEE AF-2, WHICH HAD CONVERGED FROM HIS RIGHT REAR AREA. THE MOONEY'S #1 RADIO WAS INOP & ITS #2 RADIO ANTENNA HAD BEEN VANDALIZED, THUS THE PLT WAS NOT IN RADIO CONTACT WITH ATC. THE LAST DIGIT/WHEEL ON HIS TRANSPONDER WAS STUCK ON '5' & CODE 1205 WAS BEING TRANSMITTED. THE TRANSPONDER HAD NO MODE 'C' ALT REPORTING CAPABILITY. ALL OF THE BACKCOURSE APCH WAS OUTSIDE THE TCA.
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 Mooney M20C final · quoted from the NTSB record
DURING ARRIVAL, A BOEING VC-137B-BN, USAF #58-6970, OPERATING AS AIR FORCE 2 (AF-2), WAS CLEARED FOR A LOCALIZER BACK- COURSE APCH. AT 1442:49, TRACON ADVISED AF-2 OF TRAFFIC AT ITS 10 O'CLOCK POSITION AT 2 MI, ALT UNKN. AT 1443:11, TRACON ADVISED AF-2 THE TRAFFIC HAD MOVED TO ITS 11 O-CLOCK POSITION AT 1-1/2 MI. AF-2 ACKNOWLEDGED BOTH TRANSMISSIONS. AT 1443:29, AF-2 ADVISED THAT THE FLT WAS CHANGING ITS FREQ TO BOEING TOWER. SHORTLY THEREAFTER, THE ACFT CMDR OF AF-2, SEATED IN THE RIGHT, SAW THE TRAFFIC, A MOONEY M20C, N6507U, ON A COLLISION COURSE. HE TOOK CONTROL & INITIATED EVASIVE ACTION. THE PLT OF N6507U WAS CRUISING AT 2,500 FT OUTSIDE THE SEATTLE TCA & DID NOT SEE AF-2, WHICH HAD CONVERGED FROM HIS RIGHT REAR AREA. THE MOONEY'S #1 RADIO WAS INOP & ITS #2 RADIO ANTENNA HAD BEEN VANDALIZED, THUS THE PLT WAS NOT IN RADIO CONTACT WITH ATC. THE LAST DIGIT/WHEEL ON HIS TRANSPONDER WAS STUCK ON '5' & CODE 1205 WAS BEING TRANSMITTED. THE TRANSPONDER HAD NO MODE 'C' ALT REPORTING CAPABILITY. ALL OF THE BACKCOURSE APCH WAS OUTSIDE THE TCA.
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 Boeing VC-137B-BN from the NTSB's investigation tables, in plain English
Pilot
- Certificate: military
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 4,602 hours in all
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 258,000 lb
- Landing gear: retractable
- Engine: P&W TF-33 (turbofan); 0 hours total
The flight
- Departed from: GEG Spokane WA
- Destination: BFI Seattle WA
- Flight plan: IFR
- Runway 31L, 10,000 ft by 200 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 060° at 3 knots
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 55°F (13°C), dew point 37°F (3°C)
- Altimeter: 30.00 inHg
- Observation at 9:48 pm from BFI, 8 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 16 | |||
| Passengers | 33 |
The factual record for the Mooney M20C from the NTSB's investigation tables, in plain English
Pilot
- Certificate: private
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 1,800 hours in all
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: annual inspection
- Maximum gross weight: 2,575 lb
- Seats: 4
- Landing gear: retractable
- Engine: Lycoming O-360 (piston); 0 hours total
The flight
- Departed from: S44 Spanaway WA at 9:25 pm
- Destination: S88 Arlington WA
- 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 USAF the same tail number, which may have belonged to a different aircraft at the time
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 never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.