1979 — June 11, US Forest Service Plane Crash, Selway River, Nez Perce Nat. Forest, ID-10

—  10  Aviation Safety Network. Accident Description. US Forest Service, 11 June 1979.

—  10  Baugher. 1943 USAAF Serial Numbers (43-5109 to 43-52437). 11-7-2011 rev.

 

Narrative Information

Aviation Safety Network:

“Date:                          Monday 11 June 1979

“Time:                         ca 09:45

“Type:                         Douglas C-47A-90-DL (DC-3)

“Operator:                   U.S. Forest Service

“Registration:              N148Z

“C/n / msn:                  20422

“First flight:                1944

“Engines:                     2 Pratt & Whitney R-1830-92

“Crew:                         Fatalities: 2 / Occupants: 2

“Passengers:                Fatalities: 8/ Occupants: 10

“Total:                         Fatalities: 10 / Occupants: 12

“Airplane damage:      Destroyed

….

“Location:                   48 km (30 mls) NE of Elk City, ID

“Crash site elevation:  610 m (2001 feet)

“Phase:                        En route (ENR)

….

“Departure airport:      Grangeville-Idaho County Airport, ID, United States of America

“Destination airport:   Moose Creek Airstrip, ID….

 

Baugher: “Douglas C-47A-90-DL….15956 (c/n 20422) delivered to USAAF, converted to EC-47A. To civil for U.S. Department of Justice (Immigration & Naturalization Service) as N3630G, to N148Z for the US Forest Service. W/o Jun 11, 1979 when one engine caught fire and separated from the wing. A forced landing was carried out on the Selway River. 48 km (30 mls) NE of Elk City, ID, 10 fatal.” (Baugher. 1943 USAAF Serial Numbers (43-5109 to 43-52437). 11-7-2011.)

 

FitzPatrick: “June 11, 1979 was a beautiful day in the Selway-Bitterroot Wilderness Area of northeast Idaho [Nez Perce National Forest]. The weather in the area was reported as generally clear with a thin layer of overcast clouds at 25,000 feet above ground level. The visibility was between 30 to 40 miles and the wind speed was four knots….

 

“A Forest Service owned and operated Douglas Commercial (DC)-3 C-47 and its two person crew started their day dispatched from the Grangeville, Idaho Airport to transport personnel and gear to the Moose Creek Ranger Station up the Selway River, a distance of about 60 miles. On board the aircraft were 11 Forest Service employees (which included the pilot and copilot), one volunteer, 3,100 pounds of cargo, and two canines. Some of the passengers were going to be taking part in training so that they could provide guidance and direction to wilderness users and other passengers were enroute to check the new water system installed at the Ranger Station.

 

“The aircraft had been configured for smokejumper missions and consequently all of the passengers were sitting on the port side of the aircraft facing the cargo on the other side. The cargo was held in place with retaining straps.

 

“The pilot radioed upon take off at 0928 hours Pacific Daylight Time (PDT). The pilots began to fly the normal route, over the river, and to the Ranger Station. Their next radio check-in would be due in 20 minutes, about 0950 PDT.

 

“When the Nez Perce National Forest Dispatch Office could not contact the DC-3 and determined her to be late for arrival at the Ranger Station, a search aircraft was dispatched from the Grangeville Airport. The time then was 1030 PDT. This search aircraft picked up the Emergency Locator Transmitter (ELT) signal emanating from the DC-3. A second fixed-wing aircraft and a helicopter were then dispatched to assist the search. The DC-3 was visually located at 1200 PDT.

 

“While the search was in progress, an aircraft with 14 rescue-trained smokejumpers was dispatched from the Northern Region, Regional Fire Center in Missoula, Montana. This group included seven certified Emergency Medical Technician’s (EMT’s). All 14 jumped to the mishap sight soon after it was located.

 

“The aircraft was found in the Selway River, approximately ten miles downriver from the Ranger Station. It had broken up and sections of the wreckage were scattered approximately six miles downstream by a rapid current. The location was a steep, timbered, rocky-river canyon at an elevation of 2,000 feet mean sea level (MSL). Three passengers survived the mishap; however, one of these survivors succumbed to his injuries before he could be transported to the hospital. Search, rescue, and recovery efforts continued until July 14, 1979, when all victims were accounted for.

 

“The DC-3 had apparently developed engine problems during their flight. Two observers, one a private airplane pilot, watched the aircraft take off at the Grangeville Airport. These observers reported black smoke coming from the right engine for a short period during takeoff. The smoke stopped as the aircraft circled the airport. Both observers felt the smoke was not excessive or unusual, but rather the result of a “too-rich” fuel mixture.

 

“There were also indications that the DC-3’s left engine experienced problems during its flight. The survivors reported that just prior to shutting down and feathering the left engine, the pilot made an announcement to the passengers that he had made a decision to return to the Grangeville Airport.

 

“The aircraft was observed experiencing engine trouble a few miles before the mishap site. Several visitors who were rafting and backpacking in the wilderness area observed the aircraft as it proceeded on its flight path up the river. At least three people took photos of it during the interval between the time that vapor trailed from the right engine until it was approaching the impact point. From those accounts and from those photographs, it was known that the right engine burned and fell off the wing about three miles before impact.

 

“The aircraft continued approximately three and one half miles upstream in a narrow canyon in powerless glide after the right engine fell off.

 

“The pilots evidently attempted to land in the river. During this maneuver, the aircraft hit a tree and nosed into the river. Upon impact, the aircraft broke up. All major sections were located and retrieved. Minor pieces had scattered along several miles of the river. A checkpoint was established downstream early in the recovery process so that no aircraft wreckage or victim passed that point. The river was reportedly at a high water stage….

 

“It was determined that the left engine failed (or was shut down) in flight, about 20 minutes after takeoff from the airport. Presumably this was the result of rising temperature of nose case components and lubricating oil and low oil pressure. The left propeller was apparently feathered immediately after the engine failed (or was shut down) in flight.

 

“The right engine “blew a jug” on cylinder number eight and burst into flame within perhaps 10 to 30 seconds from the time the left engine stopped. The right engine separated from the wing with an explosive sound within perhaps 10 to 30 seconds from the time it burst into flame.

 

“The time span from the failure of the left engine through impact was probably three to four minutes. The coincidence of the two engines failing within less than one minute of each other during flight was extraordinary with a probability of occurrence greater than one million to one.

 

“During the powerless glide, perhaps altering its glide path and flight attitude immediately before impact, the aircraft struck a tree with its left wing about 100 to 200 feet before impact into the river. Based upon survivors’ statements and the damage to the wreckage, it was estimated that the aircraft’s attitude upon impact was downward (perhaps 15 to 20 degrees) and the left wing was low (perhaps 15 to 20 degrees).

 

“The investigation team examined all aircraft maintenance records. They determined this aircraft had a 100-hour inspection on September 19, 1978. Inspection of the number one engine (left or port side) had been deferred since it was scheduled for replacement. On May 30, 1979, the “preseason inspection” was completed on the airframe and right engine only. The time on the number two engine (right or starboard side) was 1,069.6 hours at that time. The logbook stated that the left engine had been replaced that same day. Actual time on the left engine at the time of the mishap was 8.5 hours. Actual time on the right engine at the time of the mishap was 1,078 hours.

 

“The contractor who installed the left engine and nose case assembly stated that he was not shown any serviceable tags or certification for the engine when it was delivered to him for installation.

 

“The origin of the right engine is unknown. It was received for overhaul with a total time of approximately 8,000 hours. It was overhauled to zero hours on Feb. 6, 1973. It was installed on this aircraft at airframe time of 11,340 hours, 25 minutes.

 

“Engine teardown analysis concluded the following causes for the engines failures:

 

“Left engine:

Crankshaft to propeller shaft oil transfer pipe left out upon assembly of engine and nose case.

 

Overheating of oil and nose case gear as evidenced by discoloration of gears and metallic analysis.

 

Right engine:

Cylinder number eight parted at lower skirt in a pre-existing crack.

 

Both bronze and steel washers were found on the cylinder hold-down studs. Studs were broken and nuts were loose and missing.

 

Examination of the studs holding cylinder number eight in place showed four studs were broken and missing. One stud had a missing nut and two studs had loose nuts. All seven of the studs above were adjacent in the upper left quadrant of the flange, which holds the cylinder to the engine main case.

 

“In the metallurgical report that accompanied the teardown analysis, three studs holding cylinder number eight in place showed marks of fatigue failure to varying degrees and one yielded under tensile stress. The cylinder flange showed fatigue marks around one of the studs.

 

“Both emergency fluid shutoff valves had been pulled, which stopped fuel and oil flow from passing through the firewalls in the nacelles….” (FitzPatrick. United States Department of Agriculture Forest Service Fatal Aviation Accident History. 7-28-2004 modification, pp. 85-87.)

 

Newspaper

 

June 12, United Press International: “Grangeville, Idaho (UPI).  A Crippled DC-3 searching Monday for a flat spot to land in rugged north Idaho wilderness plunged into the swift-moving Selway River.  At least two of the 12 Forest Service employees aboard survived, including one man who hiked 10 miles to safety. The plane was carrying the employees on a 32-minute flight to a wilderness orientation school in Grangeville when one engine apparently burst into flames, then fell from the aircraft. It crashed into the river while the pilot was searching for a flat stretch of the river on which to set down.” (UPI, “Forest Service DC-3 Crashes After Losing Engine in Idaho,” June 12, 1979.)

 

Sources

 

Aviation Safety Network. Accident Description. US Forest Service, 11 June 1979. Accessed 7-22-2017 at: http://aviation-safety.net/database/record.php?id=19790611-0

 

FitzPatrick, Candy S. Rock (Compiler). United States Department of Agriculture Forest Service Fatal Aviation Accident History. 7-28-2004 modification, 117 pages. Accessed 7-22-2017 at: https://www.fs.fed.us/fire/av_safety/assurance/mishaps/fatal_aviation_accident_history.pdf

 

United Press International. “Forest Service DC-3 Crashes After Losing Engine in Idaho,” June 12, 1979. Accessed at: http://www.newspaperarchive.com/freepdfviewer.aspx?img=7709153