1956 Niles Canyon Douglas R5D-2 crash
United States Marine Corps Douglas R5D-2 Skymaster · Deviation from prescribed flight path, premature descent in low visibility
From Marine Corps Air Station El Toro to Naval Air Station Alameda
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- Event fatalities
- 40 · all aircraft and ground
- Ground fatalities
- Unknown
- Occupants
- Unknown
- Survivors
- 0
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Military
Douglas R5D-2 Skymaster
- Aircraft type
- Douglas R5
- Category
- Airplane · from aircraft type
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- WC 116
- Operator
- United States Marine Corps
- Onboard fatalities
- 40
- Route
- From Marine Corps Air Station El ToroTo Naval Air Station Alameda
Cause areas
- Personnel issues › Task performance
From the investigation findings the Wikipedia article reports, sorted into the NTSB's cause areas with AI assistance.
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
On 17 February 1956 in California a United States Marine Corps Douglas R5D-2 Skymaster flying from Marine Corps Air Station El Toro to Naval Air Station Alameda crashed on approach north of Niles Canyon, about 3.5 mi northeast of Niles, California. All 35 marines and 5 crew members died. A Marine Corps board of inquiry determined that the crash was due to "pilot error".
It was the first time this type of aircraft crashed and the third major airplane crash in the Niles Canyon area in the five years since the crash of United Air Lines Flight 615 near Decoto in August 1951.
Flight and crash
The Douglas R5D-2 Skymaster, Bureau Number 39116, and used by United States Marine Corps Marine Transport Squadron 152, departed Marine Corps Air Station El Toro at 10:30 am for a routine flight to Naval Air Station Alameda. Aboard were 35 American Marines from Marine Corps Base Camp Pendleton en route to duty in Hawaii and five crew members from El Toro.
After circling for thirty minutes because of bad weather, the pilot advised Oakland Municipal Airport at 1:42 pm that he was approaching NAS Alameda on descent. However the aircraft flew through low overcast and drizzling rain to collide with a steep canyon wall at 1:45. It had flown over Sunol ridge, crossed Stonybrook Canyon where it was seen by an aircraft technician who lived in the area, just barely cleared the west wall of Stonybrook Canyon and crashed into a box canyon on Walpert Ridge about 3.5 mi northeast of Niles, California. Initial reports assumed that an explosion occurred in the air. The aircraft broke up and burned, scattering debris over 300 yards.
Investigation and cause
Investigation
Lee Housman, the Oakland air traffic controller at the time of the accident, told investigators that Major Watson first contacted the control tower shortly after 1 pm. Watson was told to join the eight other planes in holding patterns in the skies over the area, awaiting clearance to land because of poor visibility. "We brought him down 1,000 feet at a time," Housman said, "Then, at 13:42 he reported he was at 3,500 feet, and we told him to begin his approach. His voice was calm, and everything appeared to be normal." The plane crashed three minutes later at an elevation of 1330 feet. Housman said he couldn't explain why the plane lost so much altitude so quickly, if it did at all. The pilots could have mistaken their altitude, but Ray Stepan said they had to have been at 1600 feet to clear the side of Stonybrook Canyon opposite him. Housman said Watson's last communication with him was that he was on the beam of the Newark radio beacon, meaning he was on course, but the plane crashed about six miles northeast of the approach lanes to the naval airstation.
The Marine Corps board of inquiry into the cause of the crash found that the flight crew's deviated from prescribed flight path, that they deviated from the radio beacon and made the descent in an unprescribed manner.
Text from the Wikipedia article “1956 Niles Canyon Douglas R5D-2 crash” (revision 1320555403, retrieved 2026-09-18) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out. Read the article
Sources
Wikipedia article: 1956 Niles Canyon Douglas R5D-2 crash
- Revision
- 1320555403 · 2025-11-05 · retrieved 2026-09-18
- Wikidata
- Q20986949
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
Where each value comes from
- Record
- Wikipedia article "1956 Niles Canyon Douglas R5D-2 crash" (page 74184227, revision 1320555403)
- Date
- Wikipedia infobox: date
- Place and country
- Wikipedia infobox: site
- Map position
- Wikipedia article coordinates
- Aircraft, operator and route
- Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- operator named as an armed force or military unit in the infobox
- Fatalities
- Wikipedia infobox: aircraft fatalities
- Ground fatalities
- not stated in the Wikipedia infobox
- Summary
- Wikipedia infobox: summary
Source notes (1)
- Wikipedia · Facts from the Wikipedia article's infobox and coordinates, not checked against an investigation report. Independent review pending.