History of Flight
On July 4, 2009, at approximately 1720 eastern daylight time, a Piper PA-25-235, registration N4898Y, was substantially damaged during a forced landing near Westerly State Airport (WST), Westerly, Rhode Island. The certificated commercial pilot was not injured. The banner tow flight was conducted under Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed.
According to the pilot, earlier that day he flew the airplane on another banner-tow flight lasting about 3 hours and 45 minutes. After landing, he refueled from the self-service facility at WST. He checked the auxiliary tank drain and fuel strainer for water. No water was observed in the fuel from the auxiliary tank, but about an inch of water was seen in the first sample from the fuel strainer; subsequent checks yielded less water. He repeated the process until no more water was observed, then departed on the accident flight.
The accident flight lasted about 3 hours; the pilot reported the flight was "bumpy." When inbound and approximately 2 miles from WST, the engine lost all power at an indicated altitude of about 1,000 feet. The pilot turned toward a golf course, enriched the mixture, applied carburetor heat, and attempted to restart the engine. The engine did not restart, and the pilot jettisoned the banner when realizing the airplane could not reach the golf course. He steered for "the smallest trees in the least populated area." The airplane touched down in a clearing and struck a fence during rollout.
Personnel Information
FAA records indicated the pilot held a commercial pilot certificate with airplane single-engine land, multiengine land, instrument airplane, and glider ratings. He had 1,334 total flight hours, including 27 hours in the accident airplane make and model. His most recent flight review was completed in January 2009, and his most recent FAA second-class medical certificate was issued in April 2009.
Aircraft Information
The PA-25 series was designed by Piper Aircraft as an aerial application airplane, certificated in the restricted category under type certificate 2A10. The accident airplane was manufactured in 1968 and equipped with a Lycoming O-540 series engine. It originally had a single 38-gallon fuel tank between the engine and cockpit; unusable fuel was 12 pounds (approximately 2 gallons) per type certificate data sheet.
Piper Service Spares Letter number 413, dated May 8, 1998, stated that Piper sold the PA-25 series to a manufacturer in Argentina, effective April 15, 1998, and no longer provided support.
FAA airworthiness and registration documentation showed a banner tow hitch and release system installed in July 2003. The operator, Simmons Aviation Services, purchased the airplane in January 2005. In April 2005, agricultural agent hoppers were removed and the airplane was converted to normal category per type certificate 2A8. In September 2005, an auxiliary fuel tank and associated plumbing installed by "persons unknown" were removed, and the fuel system returned to original stock configuration. No documentation was found regarding the original auxiliary tank installation.
In June 2006, an aluminum auxiliary fuel tank with 38.5-gallon capacity (limited to 25.0 gallons) was fabricated and installed, along with a polyurethane tubing sight gauge calibrated in 10-gallon increments for ground and level flight attitudes. A pilot-controlled electric pump transferred fuel from the auxiliary to main tank at 0.5 gallons per minute. The documentation indicated a dedicated sump drain for the auxiliary tank but did not specify its location relative to the fuel line pickup.
Maintenance records showed the most recent annual inspection was completed on July 3, 2008, with total time in service of 7,183 hours, hour meter 2,554 hours, engine total time 3,359 hours, and engine 1,702 hours since major overhaul.
According to the pilot, the manually-controlled electric fuel pump transferred fuel from the auxiliary to main tank, and the engine drew fuel from the main tank. The auxiliary tank had a dedicated sump drain; the main tank did not. A fuel strainer was located between the main tank and engine.
Meteorological Information
The 1653 automated weather observation at WST included winds from 250 degrees at 10 knots gusting to 15 knots, scattered clouds at 6,000 and 7,000 feet, temperature 23°C, dew point 16°C, altimeter 29.76 inches of mercury. Visibility was not reported.
Wreckage and Impact Information
FAA inspectors at the scene reported that the main landing gear was collapsed, and leading edges of both wings had multiple impact damage sites. Engine controls were operational and functioned as intended. Approximately 10 gallons of fuel remained on board; inspectors did not specify which tank(s). The carburetor bowl contained "plenty of fuel" but also a small amount of water. A sample from the fuel strainer also yielded a small amount of water. Together, the two sources (several ounces of fuel) yielded approximately 1/2 ounce of water. The airplane was secured for further examination, and inspectors instructed the operator not to work on it until further determinations.
Additional Information
Engine Examination and Test Run
On July 16, 2009, two FAA inspectors revisited the airplane at the operator's facility. Upon arrival, no fuel was in the airplane. The operator stated that after the accident, he removed approximately 4 gallons of fuel from the main tank, and the auxiliary tank was empty. No witnesses were present during fuel removal.
Inspectors noted that the airplane had a float-type fuel quantity gauge on the main tank; the auxiliary tank had no gauge. The main tank gauge was mounted on the upper fuselage skin about 3 feet ahead of the pilot, enclosed in a crazed clear plastic housing that prevented reading.
An engine cylinder compression check with 80 psi input revealed four cylinders with residual pressure about 70 psi and two with 50-60 psi. Attempts to verify magneto and ignition by hand-rotating the propeller and observing for sparks from plug leads were inconclusive; appearance of spark plug electrodes was not provided. After adding fuel to the main tank, the engine started and ran normally with no anomalies.
Fuel Vendor
FAA inspectors reported that the fuel vendor checked its tanks and found no water. The vendor stated that no other airplanes that received fuel experienced fuel contamination problems, including water in fuel.
Operator Comments
The operator told FAA inspectors that the pilot was new to this make and model and might not have leaned the engine sufficiently, implying that insufficient leaning could increase fuel flow and potentially lead to fuel exhaustion or starvation.
Carburetor Icing
Temperature and dew point values at the approximate time and location of engine failure indicated a relative humidity of approximately 65 percent. When plotted on a carburetor ice chart, the point fell in the region labeled "Serious Icing at Glide Power," approximately midway between "Icing - Glide and Cruise Power" and "Serious Icing - Cruise Power."