Skip to content

Atlas / NTSB / ATL97LA012

NTSB CAROL · Event

Event ATL97LA012

1996-10-31 DORADO, Puerto Rico Airport · SIG Serious 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

failure of the #11 cylinder on the right (#2) engine, which resulted in an in-flight fire and loss of power in that engine; and a malfunction/failure of the #2 feathering system, which led to a subsequent forced landing before the flight crew could return to the airport. A factor related to the accident was failure of the flight crew to increase the left (#1) engine rpm (in accordance with emergency procedures) after loss of power in the #2 engine.

Factual narrative

On October 31, 1996, about 0330 Atlantic standard time, a Douglas C-47, N37AP, collided with the ground during a forced landing at Dorado,, Puerto Rico. The airplane was operated by Flamenco Airways under the provisions of Title14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed. A flight plan was not filed for the positioning flight between the Fernando Luis Ribas Dominicci (SIG) airport and the Luis Munoz Marin International Airport (SJU). There were serious injuries to the captain and first officer, minor injuries to the airplane loader, and the airplane was substantially damaged. Origination of the flight was the Dominicci Airport, San Juan, Puerto Rico, minutes prior to the accident. The flight crew reported that after takeoff on runway 9, the airplane was turned left, and headed west, to climb. During the climb, about 1,0000 feet, the right engine began backfiring. According to the pilots, sparks were observed from the front of the right engine, subsequently discovered to be from a cracked cylinder. An unsuccessful attempt was made to feather the right propeller, while attempting to position the airplane for a landing at the origin airport. The copilot reported that the airplane arrived at a position that was abeam the approach threshold for runway 9, at 500 feet above the ground, with an airspeed of about 95-100 knots. The airplane was turned south toward the departure runway. A decision was then made to divert to the international airport. According to the copilot, the throttle was placed in the maximum power position without increasing the propeller control. The airplane then turned right, back to a westerly heading, and subsequently crashed beside a canal about three miles west of the departure runway (see attached map). The Federal Aviation Administration Inspector who examined the airplane reported that the number 11 cylinder on the right engine cracked. There was evidence of fire, adjacent to the cylinder on the cowling, that consisted of scorching, sooting, and a burned through area of the underside of the right engine cowling. Both propellers were in the low pitch, high rpm position, at the accident site. He also reported that the feather hold circuit on the right engine did not hold the propeller in feather when the copilot attempted to feather the right propeller. Although the copilot indicated this had occurred previously, the maintenance records did not contain previous discrepancies regarding this anomaly. The inspector indicated that the operator attempted to test the feathering system after the engine had been recovered from the crash site. When the inspector arrived at the recovery location for the engine, the feathering pump would not operate. The inspector stated he observed the right fuel selector on the right main tank, in the wreckage. A copy of the DC-3 emergency check list was provided by the inspector. The check list indicates that V2 is 85 knots, that a failed engine's propeller should be feathered, and that the affected engine's fuel selector should be placed "OFF" in the event of a fire. After takeoff from runway 9, a climbing left turn was made. At about 1,000 feet, the #2 (right) engine backfired, emitted flames, & lost power. The captain instructed the copilot to feather the #2 propeller, which the copilot initiated with the feathering button. When the captain requested gear & flap extension, the copilot released the feathering button which did not remain engaged, contrary to system design. The airplane had arrived on a left downwind abeam the landing area at 500 feet & 95 to 100 kts. The captain turned toward the runway, then he ordered the gear & flaps to be retracted & initiated a go-around by increasing the left throttle without increasing propeller speed. A right turn was then made, & the airplane eventually crashed about 3 miles from the runway. During a postaccident examination, the propellers were found unfeathered, & the right engine fuel selector was in the main tank position. The emergency procedure listed the best single engine speed as 85 kts. The procedure for engine fire/failure was to feather the propeller & to move the respective fuel selector to 'OFF.' Examination revealed the number 11 cylinder on the right engine was cracked. There was evidence of fire, adjacent to the cylinder on the cowling, which consisted of scorching, sooting, & a burned through area of the underside of the right engine cowling. The copilot indicated a previous problem with the feathering system, but maintenance records did not contain any previous discrepancies regarding this anomaly. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1996_ATL97LA012.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

Related research

What the literature says.

Academic papers and agency reports matching this event's aircraft type or causal vocabulary (go-around, maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.

Browse the full corpus — academia portal ↗