Waco UPF-7 N20971
22 April 1995 · Chino, California, United States · No injuries
Summary
On 22 April 1995 at about 17:51 local time, a Waco UPF-7 registered N20971 was involved in an accident near Chino, California, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 17:51
- Classification
- Accident
- Location
- Chino, California, United States
- Nearest airport
- Chino (CNO)
- Coordinates
- 33.9992, -117.6794
- Aircraft
- Waco UPF-7
- Registration
- N20971
- Category
- Airplane
- Engines
- 1
- Operator
- Not recorded
- Operating rule
- Part 91: General Aviation
- Purpose of flight
- Personal
- Phase of flight
- Not recorded
- Aircraft damage
- Substantial
- Weather
- VMC
- Light
- Day
- NTSB number
- LAX95LA166
People
Nobody was injured.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 1 |
Probable cause
failure of the attachment link for the master cylinder return spring, which allowed the left brake to lock.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
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.
Quoted verbatim from the NTSB record.
Other Waco UPF-7 accidents
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 29 Sep 1995 | Waco UPF-7 | Staten Island, New York, United States | - | No injuries | - |
| 18 Aug 1995 | Waco UPF-7 | Anchorage, Alaska, United States | Classic Air Ventures | Serious injuries | - |
| 25 May 1996 | Waco UPF-7 | East Canton, Pennsylvania, United States | - | Minor injuries | - |
| 4 Jun 1994 | Waco UPF-7 | Good Hope, Illinois, United States | - | Fatal | 1 |
| 27 Apr 1994 | Waco UPF-7 | Lander, Wyoming, United States | Ulrich, Philip J. | Minor injuries | - |
| 12 Jul 1997 | Waco UPF-7 | Springfield, Illinois, United States | - | No injuries | - |
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 20 Jun 1995 | Ed Bergreen KIS | San Leandro, California, United States | - | Minor injuries | - |
| 23 Jun 1995 | Spreuer COZY | Oceanside, California, United States | - | No injuries | - |
| 26 Jun 1995 | Cessna 182P | Susanville, California, United States | - | No injuries | - |
| 28 Jun 1995 | Cessna 150M | Turlock, California, United States | - | Minor injuries | - |
| 24 Jun 1995 | Piper PA-28-181 | Palm Springs, California, United States | Alan L. Kaplan | No injuries | - |
| 24 Jun 1995 | Piper PA-34-200 | Avalon, California, United States | Aero Club | No injuries | - |