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Accidents · NTSB WPR14LA025 · Final report

Aviat S2 and Cessna 172 - S accident near Livermore, California, October 20, 2013

On October 20, 2013 at about 8:59 pm local time, 2 aircraft, Aviat S2 (N15TA) and Cessna 172 - S (N698SP), were involved in the same accident near Livermore, California (Livermore Municipal airport). No one was hurt; 4 people were on board or involved. The weather was visual conditions (good weather).

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The NTSB's probable cause their words, unchanged

Failure of the pilots of the Pitts airplane to maneuver the airplane as necessary to observe the taxi route and avoid the Cessna airplane ahead. Contributing to the accident was the local controller's failure to provide the required warning of traffic ahead to the pilots of the Pitts airplane when clearing the Pitts to taxi.
Failure of the pilots of the Pitts airplane to maneuver the airplane as necessary to observe the taxi route and avoid the Cessna airplane ahead. Contributing to the accident was the local controller's failure to provide the required warning of traffic ahead to the pilots of the Pitts airplane when clearing the Pitts to taxi.

Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.

What the record shows

Date
October 20, 2013 · about 8:59 pm local time
Place
Livermore, California · Livermore Municipal · map
Type
Accident
Injuries
No one was hurt; 4 people were on board or involved.
Weather
visual conditions (good weather)
Aircraft 1
Aviat S2 C, built 2001
Registration
N15TA · registry record · serial 6045
Damage
Substantial damage
Flight
Instructional flight · general aviation rules (Part 91)
Aircraft 2
Cessna 172 - S, built 2000 · all 172 - Ss on the register
Registration
N698SP · registry record · serial 172S8639
Damage
Substantial damage
Flight
Instructional flight · general aviation rules (Part 91)

The NTSB's narrative for the Aviat S2 final · quoted from the NTSB record

While taxiing after landing at a controlled airport, a Pitts tailwheel-equipped airplane collided with a Cessna that was standing with its engine operating. Both airplanes were on instructional flights with a flight instructor and a rated pilot who was receiving instruction aboard. The airport was equipped with two parallel runways, designated as 25L and 25R. Taxiway G was situated at the end of 25L, was oriented perpendicular to the runways, and extended slightly south of 25L where it terminated at a parallel taxiway. The air traffic control tower (ATCT) was staffed by four persons serving three positions. One person was serving as controller in charge (CIC), one person was serving as local controller (LC), and two people were assigned to the ground controller (GC) position. A controller-in-training (CIT) was actively performing the GC duties, and he was being trained by a full performance level controller. The Cessna landed on 25L and, as instructed by the LC, exited south onto taxiway G, stopped, and called the GC to obtain clearance to taxi; however, the GC did not respond to the taxi request. The Pitts then landed on runway 25R, and the LC instructed the pilots to turn the airplane left onto taxiway G, hold short of 25L, and remain on the LC's frequency, which the pilots of the Pitts did. At that point, the two airplanes were facing in the same direction, separated by runway 25L and at least 300 feet. About 50 seconds after the Cessna made its taxi request to the GC, the LC cleared the Pitts to cross 25L, and although required to do so, she did not advise the Pitts of the Cessna in its path. The pilots of the Pitts were unaware of the Cessna's presence until the propeller of the Pitts struck the empennage of the Cessna. The pilots of the Pitts did not see the Cessna due to the limited forward visibility of tailwheel-equipped Pitts, their failure to S-turn while taxiing, and the limited tail-on visibility of the Cessna. Had the pilots of the Pitts performed S-turns while crossing runway 25L, the collision likely would not have occurred. In addition, the pilots of the Pitts had no expectation that the Cessna was in their path because they were operating in the movement area of a controlled airport and had not been warned of the Cessna by the LC.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

The NTSB's narrative for the Cessna 172 - S final · quoted from the NTSB record

While taxiing after landing at a controlled airport, a Pitts tailwheel-equipped airplane collided with a Cessna that was standing with its engine operating. Both airplanes were on instructional flights with a flight instructor and a rated pilot who was receiving instruction aboard. The airport was equipped with two parallel runways, designated as 25L and 25R. Taxiway G was situated at the end of 25L, was oriented perpendicular to the runways, and extended slightly south of 25L where it terminated at a parallel taxiway. The air traffic control tower (ATCT) was staffed by four persons serving three positions. One person was serving as controller in charge (CIC), one person was serving as local controller (LC), and two people were assigned to the ground controller (GC) position. A controller-in-training (CIT) was actively performing the GC duties, and he was being trained by a full performance level controller. The Cessna landed on 25L and, as instructed by the LC, exited south onto taxiway G, stopped, and called the GC to obtain clearance to taxi; however, the GC did not respond to the taxi request. The Pitts then landed on runway 25R, and the LC instructed the pilots to turn the airplane left onto taxiway G, hold short of 25L, and remain on the LC's frequency, which the pilots of the Pitts did. At that point, the two airplanes were facing in the same direction, separated by runway 25L and at least 300 feet. About 50 seconds after the Cessna made its taxi request to the GC, the LC cleared the Pitts to cross 25L, and although required to do so, she did not advise the Pitts of the Cessna in its path. The pilots of the Pitts were unaware of the Cessna's presence until the propeller of the Pitts struck the empennage of the Cessna. The pilots of the Pitts did not see the Cessna due to the limited forward visibility of tailwheel-equipped Pitts, their failure to S-turn while taxiing, and the limited tail-on visibility of the Cessna. Had the pilots of the Pitts performed S-turns while crossing runway 25L, the collision likely would not have occurred. In addition, the pilots of the Pitts had no expectation that the Cessna was in their path because they were operating in the movement area of a controlled airport and had not been warned of the Cessna by the LC.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.

The factual record for the Aviat S2 from the NTSB's investigation tables, in plain English

What happened, in order

  1. Ground collision during taxi (from runway) defining event

The NTSB's findings

  • cause Personnel issues › Action/decision › Action › Lack of action › Pilot
  • factor Environmental issues › Operating environment › Air traffic/operating proc › ATC clearance procedure › Effect on operation

Pilot

  • Certificate: private
  • Ratings: single-engine land
  • Flight time: 701 hours in all; 63 in this make and model; 12 in the last 90 days; 7 in the last 30 days; 553 as pilot in command
  • Last flight review: March 3, 2013
  • Medical certificate: Class 3 (without waivers/limitations)
  • Seat: rear
  • Injury: no injuries

Flight instructor

  • Certificate: airline transport pilot, flight instructor
  • Ratings: multi-engine land; multi-engine sea; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
  • Flight time: 10,500 hours in all; 700 in this make and model
  • Last flight review: September 25, 2013
  • Seat: frt
  • Injury: no injuries

The aircraft

  • Airframe total time: 2,153 hours
  • Last inspection: annual inspection, May 2, 2013; 85 hours since
  • Maximum gross weight: 1,700 lb
  • Seats: 2
  • Landing gear: fixed
  • Engine: Lycoming AEIO-540 (piston); 2,153 hours total
  • Operator: Attitude Aviation

The flight

  • Departed from: LVK Livermore CA
  • Destination: LVK Livermore CA
  • Flight plan: none
  • Runway 25L, 2,699 ft by 75 ft
  • A second pilot was aboard

Weather at the time

  • Light: daylight
  • Wind: from 240° at 4 knots
  • Visibility: 10 statute miles
  • Sky: clear
  • Temperature: 84°F (29°C), dew point 34°F (1°C)
  • Altimeter: 29.93 inHg
  • Observation at 8:53 pm from LVK

Injuries

FatalSeriousMinorNone
Flight crew2

The factual record for the Cessna 172 - S from the NTSB's investigation tables, in plain English

What happened, in order

  1. Ground collision during standing (engine(s) operating) defining event

The NTSB's findings

  • cause Personnel issues › Action/decision › Action › Lack of action › Pilot of other aircraft
  • factor Environmental issues › Operating environment › Air traffic/operating proc › ATC clearance procedure › Effect on operation

Flight instructor

  • Certificate: flight instructor, commercial pilot
  • Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
  • Flight time: 965 hours in all; 50 in this make and model; 39 in the last 90 days; 7 in the last 30 days; 894 as pilot in command; 180 on instruments
  • Last flight review: June 8, 2013
  • Medical certificate: Class 3 (without waivers/limitations)
  • Seat: rgt
  • Injury: no injuries

Pilot

  • Certificate: private
  • Ratings: single-engine land
  • Flight time: 141 hours in all; 2 in this make and model; 23 in the last 90 days; 6 in the last 30 days; 38 as pilot in command
  • Last flight review: August 9, 2013
  • Medical certificate: Class 3 (without waivers/limitations)
  • Seat: left
  • Injury: no injuries

The aircraft

  • Airframe total time: 3,781 hours
  • Last inspection: 100-hour inspection, October 14, 2013
  • Seats: 4
  • Landing gear: fixed
  • Engine: Lycoming IO-360 (piston); 1,584 hours total
  • Operator: West Valley Flying Club

The flight

  • Departed from: PAO Palo Alto CA
  • Destination: LVK Livermore CA
  • Runway 25L, 2,699 ft by 75 ft
  • A second pilot was aboard

Injuries

FatalSeriousMinorNone
Flight crew2

Documents from the investigation the NTSB's docket: the evidence folder behind the report

The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.

About this page

Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR14LA025.