# NTSB FTW94FA034: Cessna 172N, N4829E, Fort Collins, CO, November 15, 1993 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Field investigation · Final report - Date: November 15, 1993, 12:15 local (19:15 UTC) - Place: Fort Collins, CO - Coordinates: 40.549728, -105.059547 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.5497&lon=-105.0595&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report August 1, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 18869 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW94FA034 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18869/pdf - Page: https://openairdocs.org/ntsb/FTW94FA034 ## Probable cause POWER LOSS DUE TO THROTTLE LINKAGE DISCONNECT. FACTORS WERE MISSING COTTER KEY, IMPROPER MAINTENANCE, AND THE LACK OF SUITABLE TERRAIN FOR THE FORCED LANDING. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, takeoff - initial climb - throttle/power lever,linkage - not safetied (contributing factor) - throttle/power lever,linkage - separation (cause) - maintenance,installation - improper, company maintenance personnel (contributing factor) - Forced landing, descent - emergency - On ground/water encounter with terrain/water, landing - roll - terrain condition - none suitable (contributing factor) - terrain condition - ditch - terrain condition - slush covered - terrain condition - icy ## Analysis THE STUDENT PILOT MADE A FORCED LANDING AFTER A TOTAL POWER LOSS SHORTLY AFTER TAKEOFF. ENGINE EXAMINATION REVEALED THE COTTER PIN THAT FITTED INTO THE LOCKING NUT ON THE THROTTLE LEVER WAS MISSING. THE THROTTLE LEVER SERRATED SURFACES WERE NOT MESHED AND WERE RIDING ON TOP OF EACH OTHER. THE THROTTLE VALVE WAS CLOSED BECAUSE THE THROTTLE OPENING SPRING, DESIGNED TO FULLY OPEN THE THROTTLE IN CASE OF THROTTLE LEVER OR CABLE SEPARATION, WAS BROKEN. THREE DAYS BEFORE THE ACCIDENT, THE THROTTLE SHAFT WAS REMOVED AND INSPECTED FOR WEAR. THE MECHANIC SAID HE WAS 'ALMOST SURE' HE INSERTED THE COTTER PIN WHEN HE REINSTALLED THE CARBURETOR. THIS WAS THE FIRST FLIGHT AFTER THE MAINTENANCE WAS PERFORMED. ## Factual narrative HISTORY OF FLIGHT On November 15, 1993, approximately 1215 mountain standard time, a Cessna 172N, N4829E, was destroyed during a forced landing in a field near Fort Collins, Colorado, after the engine lost power. The pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight. The following is based on interviews with the pilot and the Pilot/Operator Report. This was to be a student solo flight to the Fort Collins-Loveland Airport for touch-and-go landing practice. After takeoff, he made a right 30 degree crosswind noise abatement turn at an altitude between 800 and 1,000 feet above ground level (AGL), engine power decreased to idle. The pilot declared an emergency, attempted to troubleshoot the problem, then committed himself to a forced landing on a snow and ice-covered field. Braking action was nil and the airplane went down a hill and collided with an irrigation ditch. TESTS AND RESEARCH During an examination of the airplane, the following was revealed: A cotter pin (p/n 82-14, ref. no. 51) that fits into the lock nut (p/n 81-311, ref. no. 49) on the throttle lever (p/n 12-B57, ref. no. 2) was missing. The serrated surfaces of the throttle lever were not meshed and were riding on top of each other. The throttle valve (p/n 14-190, ref. no. 4) was closed because the throttle opening spring (p/n 24-A10, ref. no. 24), designed to fully open (page number. 11-42) was broken. The following entry was made in the airplane's Maintenance Discrepancy Log: "11/12/93 DISCREPANCY: Throttle shaft loose. REPAIRED OR DEFERRED: Removed carburetor and removed throttle shaft from carburetor to inspect for wear. New throttle shaft and bushings on order. Reinstalled throttle shaft with proper torque and safety. Reinstalled carburetor on aircraft. Removal and installation done in accordance with Cessna Service Manual 11-42." Similar entries were made in the airframe and engine logbooks. At the time the work was performed, the airplane;'s total time in service and tachometer reading was 4148.5. At the accident site, the tachometer read 4148.5. The airplane mechanic was asked if he recalled installing the cotter pin in the throttle lever lock nut. He answered, "I'm almost sure I did." ## Aircraft - Registration: [N4829E](https://openairdocs.org/deregistered/N4829E-1996-03-02), registration cancelled 1996-03-02, S/N 17271668 (OpenAirDocs) - Reported make and model: CESSNA 172N - Registry model: [Cessna 172N](https://openairdocs.org/model/cessna-172n) (registry code 2072434) (OpenAirDocs) - Category: Airplane - Serial number: 17271668 - Airframe hours: 4149 - Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating - Damage: Destroyed - Flight: Instructional, Part 91 - Registered owner: Northern Colorado Air Charter - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 28, 1993, 87 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; student; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 29 total, 29 in this make and model, 7 as pilot in command, 29 in the last 90 days, 15 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 25 °F, dew point 23 °F - Altimeter: 30.00 inHg - Observed at: FNL, 6 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19931115042889A](https://openairdocs.org/incident/19931115042889A), Nov 15, 1993: Cessna 172N, Fort Collins, CO, Destroyed. Aircraft landed in a ditch, circumstances unknown. ## Other investigations on N4829E (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 DEN93LA068](https://openairdocs.org/ntsb/DEN93LA068), Jun 11, 1993: Cessna 172N (N4829E), Livermore, CO, substantial damage. Probable cause: A PARTIAL POWER LOSS WHEN THE ROCKER BOX FOR ONE CYLINDER DISENGAGED. A FACTOR WAS: UNSUITABLE TERRAIN FOR A FORCED LANDING. 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.