Synopsis
On July 24, 2008, at approximately 14:38 UTC, a Cessna FR 172H, registration CS-AHX, experienced a partial loss of engine power while flying at 800 feet altitude approximately 2 nautical miles north of Faro Airport. The pilot, the sole occupant, detected the power loss through a low fuel pressure indication. Unable to maintain altitude, the pilot declared an emergency, released the towed advertising banner, and requested landing at Faro Airport. Air traffic control cleared the runway and diverted other traffic. The aircraft landed safely on runway 10 at 14:42 UTC and taxied to parking without further incident.
History of Flight
The aircraft, operated by Aero VIP Lda, departed from Portimão airfield at 14:00 UTC to perform an advertising banner towing mission along the Algarve coast. The pilot held a valid Commercial Pilot License (CPL(A)) with ratings for multi-engine, single-engine, and flight instructor, and was authorized for aerial work including banner towing until 31 July 2010. The aircraft was a Cessna FR 172H, serial number 0332, built in 1972, with a Teledyne Continental IO-360-D engine. Its Certificate of Airworthiness was valid until 28 June 2009.
Injuries and Damage
The pilot, a 27-year-old Portuguese male, was uninjured. The aircraft sustained no damage, and no third-party damage occurred.
Fuel System Examination
After landing, maintenance personnel inspected the aircraft and found the fuel supply line to cylinder #4 fractured near the injector connection. Further inspection revealed that the line had been rubbing against an alternate air duct, causing wear at the friction point. Notably, a similar failure had occurred 11 days earlier with the fuel line to cylinder #3. In response, all fuel supply lines had been replaced with new ones. The removed lines were subsequently pressure- and torque-tested in a bench test and performed adequately, ruling out material fatigue due to pressure or over-tightening as the cause of the fracture.
Meteorological Conditions
Weather was good with clear skies, good visibility, and a strong west-southwest wind of 260 degrees at 16 knots.
Flight Operations
The pilot maintained proper communications with Faro Tower using VHF radio and transponder. The airport has a single asphalt runway 10/28, 2490 meters long and 45 meters wide. The approach was sequenced with other traffic; one aircraft on final for runway 28 was instructed to go around and hold.
Probable Cause
The incident report does not explicitly state a probable cause. The investigation identified a fractured fuel supply line to cylinder #4, with evidence of chafing against an alternate air duct. However, the report does not assign a definitive cause for the failure.