Narrative:

During a 'long cross country' training flight to meet the experience requirements for a private pilot certificate an engine failure occurred at the moment of rotation. The takeoff was aborted and the aircraft was safely taxied off the runway using remaining energy. After examination of the aircraft a large amount of water was removed from the gascolator. Both fuel tank sumps produced no water at all.the aircraft was inspected by the student pilot who claimed that fuel samples were taken from both wing tanks and the gascolator. The student had around 60 hours of flight time at the time of the incident; and the instructor was obtaining a weather briefing and filing a flight plan during the student's preflight. The instructors actions during preflight was to examine fuel quantity; oil quantity; drain the gascolator for a period of 2 seconds (without taking a sample) and perform a general walk-around of the aircraft inspecting for obvious damage and [irregularities]. Taxi and run-up were normal with no signs of engine problems prior to take-off. The previous 4 weeks it has been raining unusually in the area. The incident aircraft had been parked in a steeply inclined parking space (nose down) for the previous 4 days without being flown. 2 weeks prior to this incident the instructor was conducting an initial flight lesson for a new student in a 152. While sumping the gascolator the sample did not have the blue color of 100LL fuel; and the fuel smell was slightly less than usual. It was only after a very careful inspection which lasted more than 20 seconds (and by sumping an additional sample from a known-good fuel tank) that it was determined the sample cup initially contained only water. Because of this; fuel contamination was discussed in detail (including pictures of the sample) during the staff's monthly safety meeting a few days before this incident. While initially it was determined that the student pilot and instructor failed to notice the water contamination and the lack of blue dye in the sample cup; hours later it was realized that the samples were taken while the aircraft was parked nose-down on a steep incline. It is highly possible that the water was located in the forward portion of the fuel tanks and did not enter the fuel system until the aircraft was moved to level ground. Due to this incident; as an instructor I will no longer be using the 'timed' method of draining the gascolator which is a common practice and will instead ensure that an actual sample is taken with the sample cup from all three drain points. Additionally; close supervision of even 'experienced' student pilots will be performed; as well as other safety improvements during preflight inspection to prevent a similar incident from occurring in the future. Finally; additional scrutiny will be paid to aircraft using the parking spaces in question while sumping fuel. These spaces are not popular and are only used when required; as the incline mandates a minimum of 2 people for push-back; with three people preferred.

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Original NASA ASRS Text

Title: C172 instructor pilot reported experiencing engine failure on the takeoff roll that was later traced to water in the fuel.

Narrative: During a 'long cross country' training flight to meet the experience requirements for a Private Pilot Certificate an engine failure occurred at the moment of rotation. The takeoff was aborted and the aircraft was safely taxied off the runway using remaining energy. After examination of the aircraft a large amount of water was removed from the gascolator. Both fuel tank sumps produced no water at all.The aircraft was inspected by the student pilot who claimed that fuel samples were taken from both wing tanks and the gascolator. The student had around 60 hours of flight time at the time of the incident; and the instructor was obtaining a weather briefing and filing a flight plan during the student's preflight. The instructors actions during preflight was to examine fuel quantity; oil quantity; drain the gascolator for a period of 2 seconds (without taking a sample) and perform a general walk-around of the aircraft inspecting for obvious damage and [irregularities]. Taxi and run-up were normal with no signs of engine problems prior to take-off. The previous 4 weeks it has been raining unusually in the area. The incident aircraft had been parked in a steeply inclined parking space (nose down) for the previous 4 days without being flown. 2 weeks prior to this incident the instructor was conducting an initial flight lesson for a new student in a 152. While sumping the gascolator the sample did not have the blue color of 100LL fuel; and the fuel smell was slightly less than usual. It was only after a very careful inspection which lasted more than 20 seconds (and by sumping an additional sample from a known-good fuel tank) that it was determined the sample cup initially contained only water. Because of this; fuel contamination was discussed in detail (including pictures of the sample) during the staff's monthly safety meeting a few days before this incident. While initially it was determined that the student pilot and instructor failed to notice the water contamination and the lack of blue dye in the sample cup; hours later it was realized that the samples were taken while the aircraft was parked nose-down on a steep incline. It is highly possible that the water was located in the forward portion of the fuel tanks and did not enter the fuel system until the aircraft was moved to level ground. Due to this incident; as an instructor I will no longer be using the 'timed' method of draining the gascolator which is a common practice and will instead ensure that an actual sample is taken with the sample cup from all three drain points. Additionally; close supervision of even 'experienced' student pilots will be performed; as well as other safety improvements during preflight inspection to prevent a similar incident from occurring in the future. Finally; additional scrutiny will be paid to aircraft using the parking spaces in question while sumping fuel. These spaces are not popular and are only used when required; as the incline mandates a minimum of 2 people for push-back; with three people preferred.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.