# NTSB ANC98FA019: Cessna 207, N91029, Homer, AK, February 6, 1998 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: February 6, 1998, 12:45 local (16:45 UTC) - Place: Homer, AK - Coordinates: 59.400451, -151.320755 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=59.4005&lon=-151.3208&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed, report February 15, 2001 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 3089 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC98FA019 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3089/pdf - Page: https://openairdocs.org/ntsb/ANC98FA019 ## Probable cause A fatigue failure, and partial separation of the number 6 engine cylinder head assembly, the operator's inadequate progressive inspection performed by company maintenance personnel, and the pilot's inadvertent stall during a maneuvering turn toward an emergency landing area. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - mech failure/malf, takeoff - initial climb - engine assembly,cylinder - fatigue (cause) - maintenance,aaip/progressive program - inadequate, company maintenance personnel (cause) - engine assembly,cylinder - separation (cause) - Loss of control - in flight, maneuvering - turn to landing area (emergency) - stall - inadvertent, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - snow covered ## Analysis The certificated commercial pilot was departing on a 14 CFR 135 cargo flight. The airplane lifted off and climbed to about 200 feet. Instead of turning right toward the intended destination, the airplane began a left turn toward the runway. The angle of bank increased to about 45 degrees. The airplane then nosed down, and descended into snow covered terrain, about 200 yards north of the runway. Examination of the engine revealed the number six cylinder head was fractured, and slightly separated from the cylinder barrel. The area around the point of separation was blackened and oily. Similar discoloration was noted on the inside of the engine cowl. A metallurgical examination of the cylinder head revealed a fatigue fracture along a large segment of the thread root radius between the 5th and 6th threads. The engine's cylinder compression is part of the operator's approved airworthiness inspection program. The number six cylinder compression, recorded 121 hours before the accident, was noted as 60 PSI. The last engine inspection, 27 hours before the accident, did not include a record of the engine compression. ## Factual narrative HISTORY OF FLIGHT On February 6, 1998, about 1245 Alaska standard time, a wheel equipped Cessna 207 airplane, N91029, was destroyed by impact after colliding with terrain, at Homer, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country cargo flight under Title 14 CFR Part 135 when the accident occurred. The airplane was registered to, and operated by South Central Air Inc., Kenai, Alaska. The certificated commercial pilot, the sole occupant, received fatal injuries. Visual meteorological conditions prevailed. A VFR flight plan was filed for English Bay, Alaska. At 1242:27, the pilot made radio contact with the in-flight position at the Federal Aviation Administration's (FAA) Homer Flight Service Station (FSS). The pilot filed a VFR flight plan, and announced his departure from Homer at 1244:03. Just after departure, an electronic locator transmitter (ELT) signal was heard at the FSS. Witnesses reported the airplane departed runway 03, and climbed to about 100 to 200 feet above the ground. The airplane then began a left turn. During the turn, the bank angle increased, and the nose of the airplane dropped straight down. The airplane disappeared from view behind several trees. The accident occurred during the hours of daylight, at latitude 59 degrees, 38.958 minutes north, and longitude 151 degrees, 28.309 minutes west. CREW INFORMATION The pilot held a commercial pilot certificate with airplane single-engine land, single-engine sea, and multiengine land ratings. The pilot also held a flight instructor certificate with airplane single-engine, and instrument airplane ratings. The most recent second-class medical certificate was issued to the pilot on September 16, 1997, and contained the limitation that the pilot must wear corrective lenses. The pilot was hired by the company on June 15, 1997. On June 24, 1997, the pilot completed his initial Part 135 check ride. According to the Pilot/Operator report (NTSB form 6120.1/2) submitted by the operator, the pilot's aeronautical experience consisted of about 1,358 hours, of which 48 hours were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the report listed a total of 132 and 57 hours respectively. According to the operator, in the three days preceding the accident, the pilot accrued 7.7 hours of flight time. AIRCRAFT INFORMATION The airplane had accumulated a total time in service of 11,192.2 hours. The airplane is maintained on an Approved Airworthiness Inspection Program (AAIP). The most recent inspection (event 4), was accomplished on January, 9, 1998, 27.2 hours before the accident. The engine had accrued a total time in service of 2,559.5 hours. The maintenance records note that a major overhaul was accomplished at the operator's maintenance department on April 11, 1996, 954.4 hours before the accident. At that time, the engine was converted to a nonturbo-charged model. According to the operator's AAIP inspection schedule, a compression test of the engine's cylinders is required during Event 2, and Event 4, inspections. Event 2 and 4 inspections also include an inspection of the engine cylinders for any defects. During the most recent Event 4 inspection, the engine compression was not noted in the maintenance records. The operator's Event 4 inspection sheet did contain an employee's initials on the appropriate line for the compression check and cylinder inspection. During the previous Event 2 inspection, on October 9, 1997, 121.5 hours before the accident, the engine compression was noted as follows: Cylinder Number 1, 69 psi; Number 2, 65 psi; Number 3, 62 psi; Number 4, 60 psi; Number 5, 72 psi, Number 6, 60 psi. The engine cylinders utilized for the engine overhaul were obtained from Divco Inc., Tulsa, Oklahoma. A NU-Chrome finish was applied to each cylinder bore by Aircraft Cylinders of America, Inc., Tulsa. METEOROLOGICAL INFORMATION The closest official weather observation station is Homer, Alaska. On February 6, 1998, at 1253, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, calm; visibility, 10 statute miles; clouds, 7,000 feet broken, 9,000 feet overcast; temperature, 39 degrees F; dew point, 34 degrees F; altimeter, 29.49 inHg. COMMUNICATIONS Review of the air-ground radio communications tapes maintained by the FAA at the Homer FSS, revealed the pilot communicated with the flight service station specialist at the in-flight position. The pilot obtained a terminal forecast at 0847:55 while using the call sign of N178SC. The pilot filed a VFR flight plan for the accident flight at 1242:27. A transcript of the air to ground communications between the pilot, and the Homer FSS, is included in this report. AERODROME AND GROUND FACILITIES The Homer Airport is equipped with a single hard-surfaced runway on a 030 to 210 degree magnetic orientation. Runway 03 is 7,401 feet long by 150 feet wide. The airport elevation is 78 feet msl. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC) examined the airplane wreckage at the accident site on February 6 and 7, 1998. The fuselage of the airplane was observed in a near vertical nose down attitude in snow covered terrain. The longitudinal axis of the fuselage was oriented on a magnetic heading of 045 degrees. (All heading/bearings noted in this report are oriented toward magnetic north.) All of the airplane's major components were found at the main wreckage area. Both wings exhibited extensive spanwise leading edge aft crushing, and were oriented with the leading edge down, on about a 45 degree angle. The right wing lift strut remained attached to the wing and its lower attach point. The left wing lift strut was attached to the wing, but was separated from its fuselage attach point. The wing carry-through was broken, and crushed in an aft direction. The fuselage was oriented in a near vertical attitude. The fuselage was buckled just aft of the rear window. The flight control surfaces remained connected to their respective attach points. Due to the impact damage, the flight controls could not be moved by their respective control mechanisms, but the continuity of the flight control cables was established to the cabin/cockpit area. The flap jackscrew was not extended. The airplane's point of rest was in an area of small spruce trees. The tops of the surrounding trees were undamaged. One small tree, between 1 to 3 inches in diameter, was located near the forward portion of the airplane. It was severed into numerous sections. Each section was between 16 to 12 inches long. The ends of each section displayed a sharp cut oriented on about a 45 degree angle to the vertical axis of each section. The airplane had a vertical cargo net/barrier installed behind the pilot's seat. The net is normally installed by inserting metal fittings attached to the net, into metal anchors attached to the airframe, just aft of the cabin door opening. Several of the net straps were pulled from their attach fittings. None of the net anchors were damaged. The elevator trim tab actuator was found extended beyond the trailing edge down limit. Rescue personnel that initially responded to the accident scene, reported the trim tab was observed in a neutral position. During rescue efforts, the tail of the airplane was pulled downward, and the elevator trim cable was cut by rescue personnel. The propeller bolts attaching the prop to the engine crankshaft were sheared. The blades were loose in the hub. One propeller blade was almost straight, but it exhibited slight torsional twisting, and slight forward bending about 4 inches inboard from the tip. The second blade exhibited about 70 degree aft bending about 8 inches outboard from the hub, and slight torsional twisting. The paint on the cambered si ## Aircraft - Registration: [N91029](https://openairdocs.org/deregistered/N91029-2013-08-21), registration cancelled 2013-08-21, S/N 20700020, built 1969 (OpenAirDocs) - Reported make and model: Cessna 207 - Registry model: [Cessna T207](https://openairdocs.org/model/cessna-t207) (registry code 2073612) (OpenAirDocs) - Registry engine: [Continental GTSIO-520-C](https://openairdocs.org/engine/continental-gtsio-520-c) (registry code 17035, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: T20700020 - Airframe hours: 11192 - Engines: Continental IO-520F 300 horsepower reciprocating - Damage: Destroyed - Flight: Part 135 - Registered owner: South Central Air Inc. - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, January 9, 1998, 27 hours before - Departed: HOM - Destination: KEB, ENGLISH BAY, AK - Flight plan: VFR - Airport: PAHO, Homer, runway 3, 7,401 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 1,358 total, 48 in this make and model, 1,192 as pilot in command, 132 in the last 90 days, 57 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 7,000 ft broken - Temperature: 39 °F, dew point 34 °F - Altimeter: 29.00 inHg - Observed at: HOM ## 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 19980206002389A](https://openairdocs.org/incident/19980206002389A), Feb 6, 1998: Cessna T207, Homer, AK, Destroyed, 1 fatal. Aircraft climbed to 150 ft AGL on takeoff. Banked into steep turn and dove into snow covered ground. (.4)the certificated commercial pilot was departing on a… ## Other investigations on N91029 (2) 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 LAX78DUM04](https://openairdocs.org/ntsb/LAX78DUM04), Nov 24, 1977: Cessna T207 (N91029), Calexico, CA, substantial damage - [NTSB DEN69A0037](https://openairdocs.org/ntsb/DEN69A0037), Mar 24, 1969: Cessna T207 (N91029), Aspen, CO, substantial damage 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.