Waco UPF-7 accident near Chino, California, April 22, 1995
On April 22, 1995 at about 5:51 pm local time, a Waco UPF-7, registered N20971, was substantially damaged in an accident near Chino, California (Chino airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
failure of the attachment link for the master cylinder return spring, which allowed the left brake to lock.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 22, 1995 · about 5:51 pm local time
- Place
- Chino, California · Chino · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Waco UPF-7 · all UPF-7s on the register
- Registration
- N20971 · registry record · serial 5317
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT EXPERIENCED A DIRECTIONAL CONTROL PROBLEM DURING THE LANDING ROLL. IN HER INITIAL ORAL STATEMENT, SHE INDICATED THE DIFFICULTY WAS DUE TO THE WIND CONDITION. REGARDING HER ATTEMPT TO CONTROL THE AIRCRAFT, SHE SAID SHE THOUGHT SHE MIGHT HAVE INADVERTENTLY APPLIED THE BRAKES, WHICH HAD CAUSED THE AIRCRAFT TO NOSE OVER. A POSTACCIDENT INSPECTION OF THE AIRCRAFT REVEALED THAT THE ATTACHMENT LINK OF THE RETURN SPRING FOR THE LEFT MASTER CYLINDER HAD FAILED. ACCORDING TO THE MAINTENANCE MANUAL FOR THE HAYES NO. D-87-36 BRAKE MASTER CYLINDER, THE ASSEMBLY WAS DESIGNED SO THAT SOME BRAKE FLUID WOULD BE ADDED TO THE PRESSURE SIDE OF THE PISTON DURING THE RETURN STROKE. HOWEVER, IF THE RELIEF PORT WAS NOT OPENED BY A COMPLETE RETURN OF THE PISTON, WHEN THE BRAKE WAS RELEASED, PRESSURE COULD HAVE BUILT UP IN THE SYSTEM, CAUSING THE BRAKE TO DRAG OR LOCK.
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 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 674 hours in all; 620 in this make and model; 16 in the last 90 days; 1 in the last 30 days; 565 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: rear
The aircraft
- Last inspection: annual inspection, December 23, 1994; 13 hours since
- Maximum gross weight: 2,650 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental W670 (piston); 0 hours total
The flight
- Departed from: CNO at 5:30 pm
- Flight plan: none
- Runway 8, 4,856 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 270° at 10 knots
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Altimeter: 30.00 inHg
- Observation at 5:46 pm from CNO
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.
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.