# NTSB LAX94LA050: Cessna 172RG, N9620B, Santa Ana, CA, November 18, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: November 18, 1993, 11:07 local (19:07 UTC) - Place: Santa Ana, CA - Coordinates: 33.710048, -117.870971 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.7100&lon=-117.8710&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report September 13, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 28602 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA050 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28602/pdf - Page: https://openairdocs.org/ntsb/LAX94LA050 ## Probable cause (aircraft 2) were the CFI's inadequate supervision of the flight and his delay in taking remedial action. The dual student's excessive taxi speed and the worn right brake lining were factors in this accident. ## Probable cause (aircraft 1) were the other airplane's CFI's inadequate supervision of the flight, and his delay in taking remedial action. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water collision with object, standing - supervision - inadequate, pilot of other aircraft (cause) - remedial action - delayed, pilot of other aircraft (cause) - On ground/water collision with object, taxi - to takeoff - landing gear,normal brake system - worn (contributing factor) - supervision - inadequate, pilot in command(cfi) (cause) - remedial action - delayed, pilot in command(cfi) (cause) - taxispeed - excessive, dual student (contributing factor) ## Analysis (aircraft 2) THE AIRPLANE WAS TAXIING FOR TAKEOFF. WHEN APPROACHING A STANDING AIRPLANE HOLDING SHORT OF THE RUNWAY, THE STUDENT PILOT REDUCED THE THROTTLE AND APPLIED THE BRAKES. THE AIRPLANE BEGAN TO TURN TO THE LEFT HEADING TOWARD THE STANDING AIRPLANE AND THE STUDENT APPLIED RIGHT RUDDER, WHICH CONTROLS THE NOSE GEAR STEERING ON THE GROUND. WHEN THIS ACTION DID NOT STOP THE AIRPLANE OR ARREST THE TURN, THE STUDENT TURNED THE AILERONS. THE STUDENT TOLD THE CFI THAT SHE WAS HAVING A PROBLEM IN STOPPING THE AIRPLANE, BUT BY THIS TIME THE CFI WAS SIMULTANEOUSLY APPLYING THE BRAKES AND FULL RIGHT RUDDER, BUT WITHOUT SUCCESS. THE AIRPLANE STRUCK THE STANDING AIRPLANE'S LEFT REAR SIDE. THE EXAMINATION OF THE BRAKE SYSTEM DISCLOSED THE RIGHT BRAKE LINING WAS WORN BEYOND SERVICEABLE LIMITS AND BOTH BRAKE CYLINDERS FUNCTIONED NORMALLY. ## Analysis (aircraft 1) THE CFI AND HIS STUDENT WERE HOLDING AT THE RUNWAY APPROACH END WHEN ANOTHER AIRCRAFT STRUCK THEIR AIRCRAFT ON THE LEFT REAR SIDE. ## Factual narrative (aircraft 2) On November 18, 1993, at 1107 hours Pacific standard time, a Cessna 172RG, N9620B, was struck by a Cessna 172P, N97766, while on taxiway K while awaiting departure clearance at John Wayne Airport (SNA), Santa Ana, California. The pilots aboard both airplanes were beginning a local visual flight rules instructional flight. N9620B, operated by Lenair Aviation, SNA, sustained substantial damage; N97766, operated by American Flyers, SNA, sustained minor damage. Neither the certificated commercial pilot/flight instructor (CFI) nor the certificated private pilot/dual student aboard N9620B was injured. Neither the CFI nor the noncertificated student pilot aboard N97766 was injured. Visual meteorological conditions prevailed. The Orange County Sheriff's Department, Airport Division, conducted the initial investigation immediately following the accident. N9620B Both pilots aboard N9620B told the investigating deputy that they were holding short (facing west) of runway 19L as instructed by the ground controller. Neither pilot saw the approaching Cessna 172 (N97766) while it was taxiing north on taxiway C. N97766 The student pilot told the investigating deputy that the airplane began to veer toward N9620B. She tried to correct with the rudder (the rudder also controls the nose gear while on the ground), but got no response. She attempted to steer the airplane like a car using the ailerons, but without success. She then informed the instructor that they were going to hit the parked aircraft. The CFI told the investigating deputy that he was instructing the student and noticed she was in trouble. He attempted to turn the airplane "...using slight rudder to the right...," but got no response. He then applied full right rudder and full braking and "...leaned the throttle [mixture] in the attempts to avoid the collision...." The CFI submitted a Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2. He said in the report that as the airplane was approaching taxiway "K" the student retarded the throttle. He then instructed the student to apply the brakes while he was simultaneously applying the brakes. As the airplane veered to the left toward the standing airplane (N9620B), the CFI applied right rudder and more right brake, but without success; the airplane did not stop or arrest the left turn. The CFI pulled the mixture control before the collision. The CFI also reported that there were two other incidents where the right brake failed; one in Florida, and the other in New York. Both involved the Cessna 172 airplane. The dual student submitted a written statement to the Federal Aviation Administration (FAA), Long Beach Flight Standards District Office. The student confirmed her previous statement to the Orange County deputy and added that she thought the airplane was taxiing too fast and she fully retarded the throttle. She didn't notice any difference in the airplane's speed and she informed her instructor. He instructed her to "...brake a little...", which she did. The mechanic who repaired the airplane in Florida told National Transportation Safety Board investigators that the right brake failure was caused by a faulty "O" ring seal in the master cylinder. Safety Board investigators were unable to contact the mechanic who repaired the New York incident airplane. A Cessna Aircraft Company representative was interviewed by telephone on June 7, 1994. He told Safety Board investigators that he has no knowledge of a brake failure without a known faulty mechanism involving the accident airplane make and model. Safety Board investigators examined the brake system of N97766 on December 3, 1993. Investigators visually examined the brake linings. The brake linings did not appear excessively worn. A functional test of both brakes appeared normal. The investigators disassembled the brakes and both master cylinders. The investigators found that the right brake lining was worn to the height of the rivet heads, between 1/16 of an inch to 3/32 of an inch. The Cessna 172 maintenance manual requires replacement of the brake lining when it is worn to 3/32nd of an inch. Investigators found no discrepancies in either brake master cylinder. Examination of N97766's airframe logbooks showed that the operator was maintaining the airplane according to an "Approved Aircraft Inspection Program " (AAIP). This program requires inspection events every 75 flight hours. The operator did the last inspection, the number two (2) event, 36.7 hours before the accident. The number two (2) event did not include inspection of the brakes. The airplane had accrued 111.7 hours since the number one (1) event, which included the brake inspection. The mechanic who repaired the airplane told Safety Board investigators that he operated the right brake master cylinders for two hours after it was reassembled. The master cylinder operated normally throughout the functional test. ## Factual narrative (aircraft 1) On November 18, 1993, at 1107 hours Pacific standard time, a Cessna 172RG, N9620B, was struck by a Cessna 172P, N97766, while on taxiway K while awaiting departure clearance at John Wayne Airport (SNA), Santa Ana, California. The pilots aboard both airplanes were beginning a local visual flight rules instructional flight. N9620B, operated by Lenair Aviation, SNA, sustained substantial damage; N97766, operated by American Flyers, SNA, sustained minor damage. Neither the certificated commercial pilot/flight instructor (CFI) nor the certificated private pilot/dual student aboard N9620B was injured. Neither the CFI nor the noncertificated student pilot aboard N97766 was injured. Visual meteorological conditions prevailed. The Orange County Sheriff's Department, Airport Division, conducted the initial investigation immediately following the accident. N9620B Both pilots aboard N9620B told the investigating deputy that they were holding short (facing west) of runway 19L as instructed by the ground controller. Neither pilot saw the approaching Cessna 172 (N97766) while it was taxiing north on taxiway C. N97766 The student pilot told the investigating deputy that the airplane began to veer toward N9620B. She tried to correct with the rudder (the rudder also controls the nose gear while on the ground), but got no response. She attempted to steer the airplane like a car using the ailerons, but without success. She then informed the instructor that they were going to hit the parked aircraft. The CFI told the investigating deputy that he was instructing the student and noticed she was in trouble. He attempted to turn the airplane "...using slight rudder to the right...," but got no response. He then applied full right rudder and full braking and "...leaned the throttle [mixture] in the attempts to avoid the collision...." The CFI submitted a Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2. He said in the report that as the airplane was approaching taxiway "K" the student retarded the throttle. He then instructed the student to apply the brakes while he was simultaneously applying the brakes. As the airplane veered to the left toward the standing airplane (N9620B), the CFI applied right rudder and more right brake, but without success; the airplane did not stop or arrest the left turn. The CFI pulled the mixture control before the collision. The CFI also reported that there were two other incidents where the right brake failed; one in Florida, and the other in New York. Both involved the Cessna 172 airplane. The dual student submitted a written statement to the Federal Aviation Administration (FAA), Long Beach Flight Standards District Office. The student confirmed her previous statement to the Orange County deputy and added that she thought the airplane was taxiing too fast and she fully retarded the throttle. She didn't notice any difference in the airplane's speed and she informed her instructor. He instructed her to "...brake a little...", which she did. The mechanic who repaired the airplane in Florida told National Transportation Safety Board investigators that the right brake failure was caused by a faulty "O" ring seal in the master cylinder. Safety Board investigators were unable to contact the mechanic who repaired the New York incident airplane. A Cessna Aircraft Company representative was interviewed by telephone on June 7, 1994. He told Safety Board investigators that he has no knowledge of a brake failure without a known faulty mechanism involving the accident airplane make and model. Safety Board investigators examined the brake system of N97766 on December 3, 1993. Investigators visually examined the brake linings. The brake linings did not appear excessively worn. A functional test of both brakes appeared normal. The investigators disassembled the brakes and both master cylinders. The investigators found that the right brake lining was worn to the height of the rivet heads, between 1/16 of an inch to 3/32 of an inch. The Cessna 172 maintenance manual requires replacement of the brake lining when it is worn to 3/32nd of an inch. Investigators found no discrepancies in either brake master cylinder. Examination of N97766's airframe logbooks showed that the operator was maintaining the airplane according to an "Approved Aircraft Inspection Program " (AAIP). This program requires inspection events every 75 flight hours. The operator did the last inspection, the number two (2) event, 36.7 hours before the accident. The number two (2) event did not include inspection of the brakes. The airplane had accrued 111.7 hours since the number one (1) event, which included the brake inspection. The mechanic who repaired the airplane told Safety Board investigators that he operated the right brake master cylinders for two hours after it was reassembled. The master cylinder operated normally throughout the functional test. ## Aircraft 1 - Registration: [N9620B](https://openairdocs.org/deregistered/N9620B-2019-09-06), registration cancelled 2019-09-06, S/N 172RG0925, built 1981 (OpenAirDocs) - Reported make and model: CESSNA 172RG - Registry model: [Cessna 172RG](https://openairdocs.org/model/cessna-172rg) (registry code 2072438) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 172RG0925 - Airframe hours: 5385 - Engines: LYCOMING O-360-F1AG 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Lenair Aviation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 1, 1993, 75 hours before - Airport: SNA, John Wayne Airport ## Aircraft 2 - Registration: [N97766](https://openairdocs.org/aircraft/N97766), registered now, S/N 17276228, built 1984 (OpenAirDocs) - Reported make and model: CESSNA 172P - Registry model: [Cessna 172P](https://openairdocs.org/model/cessna-172p) (registry code 2072436) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17276228 - Airframe hours: 11831 - Engines: LYCOMING O-320-D2J 160 horsepower reciprocating - Damage: Minor damage - Flight: Instructional, Part 91 - Operator: American Flyers - Registered owner: A.T.E. Of California, Inc. - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: AAIP, November 8, 1993, 50 hours before - Airport: SNA, John Wayne Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot, aircraft N9620B; age 49; airline transport, flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 3,000 total, 90 in this make and model, 2,850 as pilot in command, 200 in the last 90 days, 85 in the last 30 days, 2 in the last 24 hours - Pilot, aircraft N97766; age 28; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 1,430 total, 900 in this make and model, 1,371 as pilot in command, 153 in the last 90 days, 54 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 5 knots - Visibility: 5 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 43 °F - Altimeter: 30.00 inHg - Observed at: SNA ## FAA reports on this event (2) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19931118044022A](https://openairdocs.org/incident/19931118044022A), Nov 18, 1993: Cessna 172RG, Santa Ana, CA, Substantial damage. Awaiting takeoff was struck from behind by N97766 that was taxiing for takeoff with CFI aboard. Blamed brakes. - [Accident 19931118044031A](https://openairdocs.org/incident/19931118044031A), Nov 18, 1993: Cessna 172P, Santa Ana, CA, Minor damage. While taxiing for takeoff veered left into a holding 172 N9620B. Right brake failed. CFI unable to stop aircraft. ## Other investigations on N9620B (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB FTW99LA216](https://openairdocs.org/ntsb/FTW99LA216), Aug 7, 1999: Cessna 172RG (N9620B), Celina, TX, substantial damage. Probable cause: The failure of the pilot in command to use all of the available runway for takeoff. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.