Piper PA-31-350 Navajo Chieftain

The twin engine airplane departed Popayán-Guillermo León Valencia Airport runway 26 at 14:06:06. The aircraft encountered difficulties to gain sufficient height. About 20 seconds after liftoff, at a speed of 82 knots, the aircraft rolled to the right then entered an uncontrolled descent and crashed onto two houses located 530 metres past the runway end. Two passengers were seriously injured and seven other occupants were killed.

In the morning, the Guatemala Army Forces were informed by ATC that a PA-31 entered the Guatemala Airspace without prior permission. The twin engine airplane crashed in a wooded area located near the farm of Sepens located in the region of Sayaxché, Petén. The aircraft was partially destroyed by impact forces and both occupants were killed. A sticker was set on the fuselage with the registration N2613 which is wrong.

The twin engine airplane departed Venezuela in the evening on a probable drug smuggling flight with an unknown destination. At 2226LT, after it entered the Dominican Airspace, a crew of the Dominican Air Force was dispatched with an Embraer EMB-314 Super Tucano but the PA-31 disappeared from radar screens at 2228LT after crashing in a sugar cane field located in the region of San Rafael de Yuma, between La Romana and Punta Cana. Due to limited visibility caused by night and poor weather conditions, SAR operations were suspended shortly after midnight. The wreckage was found in the next early morning. Nobody was found on site and the aircraft is probably written off. The registration YV312 may be a wrong one.

The commercial pilot was conducting an aerial observation (surveying) flight in a piston engineequipped multiengine airplane. Several hours into the flight, the pilot advised air traffic control (ATC) that the airplane had a fuel problem and that he needed to return to the departure airport. When the airplane was 8 miles from the airport, and after passing several other airports, the pilot informed ATC that he was unsure if the airplane could reach the airport. The final minutes of radar data depicted the airplane in a descent and tracking toward a golf fairway as the airplane's groundspeed decreased to a speed near the single engine minimum control airspeed. According to witnesses, they heard an engine sputter before making two loud "back-fire" sounds. One witness reported that, after the engine sputtered, the airplane "was on its left side flying crooked." Additional witnesses reported that the airplane turned to the left before it "nose-dived" into a neighborhood, impacting a tree and private residence before coming to rest in the backyard of the residence. A witness approached the wreckage immediately after the accident and observed a small flame rising from the area of the left engine. Video recorded on the witness' mobile phone several minutes later showed the airplane engulfed in flames. Examination of the wreckage revealed no evidence of any preimpact mechanical malfunctions or failures of either engine. The fuel systems feeding both engines were damaged by impact forces but the examined components generally displayed that only trace amounts of fuel remained; with the exception of the left engine nacelle fuel tank. Given the extent of the fire damage to this area of the wreckage, and the witness report that the post impact fire originated in this area, it is likely that this tank contained fuel. By design, this fuel in this tank was not able to supply fuel directly to either engine, but instead relied on an electric pump to transfer fuel into the left main fuel tank. Fire damage precluded a detailed postaccident examination or functional testing of the left nacelle fuel transfer pump. Other pilots who flew similar airplanes for the operator, along with a review of maintenance records for those airplanes, revealed at least three instances of these pumps failing in the months surrounding the accident. The other pilots also reported varying methods of utilizing fuel and monitoring fuel transfers of fuel from the nacelle fuel tanks, since there was no direct indication of the quantity of fuel available in the tank. These methods were not standardized between pilots within the company and relied on their monitoring the quantity of fuel in the main fuel tanks in order to ensure that the fuel transfer was occurring. Had the pilot not activated this pump, or had this pump failed during the flight, it would have rendered the fuel in the tank inaccessible. Given this information it is likely that the fuel supply available to the airplane's left engine was exhausted, and that the engine subsequently lost power due to fuel starvation. The accident pilot, along with another company pilot, identified fuel leaking from the airplane's left wing, about a week before the accident. Maintenance records showed no actions had been completed to the address the fuel leak. Due to damage sustained during the accident, the origin of the fuel leak could not be determined, nor could it be determined whether the fuel leak contributed to the fuel starvation and eventual inflight loss of power to the left engine. Because the left engine stopped producing power, the pilot would have needed to configure the airplane for single-engine flight; however, examination of the left engine's propeller found that it was not feathered. With the propeller in this state, the pilot's ability to maintain control the airplane would have been reduced, and it is likely that the pilot allowed the airplane's airspeed to decrease below the singleengine minimum controllable airspeed, which resulted in a loss of control and led to the airplane's roll to the left and rapid descent toward the terrain. Toxicology results revealed that the pilot had taken doxylamine, an over-the-counter antihistamine that can decrease alertness and impair performance of potentially hazardous tasks. Although the toxicology results indicated that the amount of doxylamine in the pilot's cavity blood was within the lower therapeutic range, review of ATC records revealed that the pilot was alert and that he was making necessary decisions and following instructions. Thus, the pilot's use of doxylamine was not likely a factor in the accident.

The commercial pilot of the multiengine airplane was the first of a flight of two airplanes to depart on the cross-country flight, most of which was over the Atlantic Ocean. The pilot of the second airplane stated that he and the accident pilot reviewed the weather for the route and the destination before departing; however, there was no record of the accident pilot receiving an official weather briefing and the information the pilots accessed before the flight could not be determined. The second pilot departed and contacted air traffic control, which advised him of thunderstorms near the destination; he subsequently altered his route of flight and landed uneventfully at the destination. The second pilot stated that he did not hear the accident pilot on the en route air traffic control frequency. Two inflight weather advisories were issued for the route and the area of the destination about 42 and 15 minutes before the accident flight departed, respectively, and warned of heavy to extreme precipitation associated with thunderstorms. It could not be determined whether the accident pilot received these advisories. Review of air traffic control communications and radar data revealed that, about 5 miles from the destination airport, the pilot of the accident airplane reported to the tower controller that he was flying at 700 ft and "coming in below" the thunderstorm. There were no further communications from the pilot. The airplane's last radar target indicated 532 ft about 2 miles south of the shoreline. The airplane was found in about 50 ft of water and was fragmented in several pieces. Postaccident examination revealed no preimpact anomalies with the airplane or engines that would have precluded normal operation. A local resident about 1/2 mile from the accident site took several photos of the approaching thunderstorm, which documented a shelf cloud and cumulus mammatus clouds along the leading edge of the storm, indicative of potential severe turbulence. Review of weather imagery and the airplane's flight path showed that the airplane entered the leading edge of "extreme" intensity echoes with tops near 48,000 ft. Imagery also depicted heavy to extreme intensity radar echoes over the accident site extending to the destination airport. It is likely that the pilot encountered gusting winds, turbulence, restricted visibility in heavy rain, and low cloud ceilings in the vicinity of the accident site and experienced an in-flight loss of control at low altitude. Such conditions are conducive to the development of spatial disorientation; however, the reason for the pilot's loss of control could not be determined based on the available information.