Incident Overview
On 18 March 2011 at 17:30 UTC, a Piper PA-28-180, registration I-ONIL, operated by Aero Club Ali Maremma, was conducting a training flight from Grosseto airport. The aircraft had three people on board: an instructor pilot, a student pilot, and a passenger. Approximately 20 minutes after takeoff, the engine stopped. After unsuccessful restart attempts, the pilot performed a forced landing on an agricultural field near Albinia, a frazione of Orbetello (Grosseto). During the landing, the soft terrain caused the nose and main landing gear legs to break, and the aircraft slid about 15 meters before coming to rest on its belly.
Injuries and Damage
The occupants in the front seats sustained minor abrasions from impact with the dashboard. The aircraft suffered deformation of one propeller blade, detachment of the landing gear legs, and damage to the wing surfaces and fuselage.
Investigation Findings
Examination immediately after the incident revealed the presence of massive water (over one liter) in the right wing fuel tank, which was in use at the time, as well as in the gascolator filter and carburetor float bowl. The aircraft had been refueled before the flight from a fixed underground fuel installation managed by the local Aero Club. Inspection of that installation found massive water throughout the dispensing circuit, from the electric pump (which was also blocked) to the transparent inspection window, flexible hose, and final dispensing filter. When the pump was activated, a continuous mixture of water and fuel was expelled.
The access pit to the underground tank showed a layer of water approximately one centimeter deep on the bottom, advanced corrosion of the tank manhole cover and associated metal pipes up to about 30 centimeters from the cover, and complete peeling and detachment of the vent tube from the cover due to corrosion. It appeared very likely that the vent tube lost integrity and detached completely during the last fuel dispensing, coinciding with the refueling of the aircraft's right wing tank. The total detachment allowed water present in the pit to pour into the tank and be drawn in during the final phase of refueling.
Following these findings, the fuel installation was rendered inoperable by removing the pump and disconnecting the pipes.
Safety Considerations
The investigation focused on adherence to maintenance and inspection procedures for fixed fuel dispensing installations, and on pilots' compliance with fuel management procedures as outlined in the aircraft operating manual. Statements from the instructor and student pilot were obtained for preventive purposes. Further examination of documentation regarding aircraft refueling from fixed installations and operation of such systems was ongoing.