# NTSB ATL93MA068: Fairchild SA227-TT, N500AK, Blountville, TN, April 2, 1993 - Type: NTSB accident investigation - Classification: Accident · Fatal · Major investigation · Final report - Date: April 1, 1993, 21:28 local (Apr 2, 1993, 02:28 UTC) - Place: Blountville, TN - Coordinates: 36.530719, -82.319145 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.5307&lon=-82.3191&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 4 fatal - Status: Completed, report March 16, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 3270 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL93MA068 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3270/pdf - Page: https://openairdocs.org/ntsb/ATL93MA068 ## Probable cause FAILURE OF THE PILOT TO FOLLOW PROCEDURES CONCERNING USE OF THE ENGINE INLET ANTI-ICE SYSTEM AND/OR CONTINUOUS IGNITION WHILE OPERATING IN ICING CONDITIONS, WHICH RESULTED IN PROBABLE ICE INGESTION AND LOSS OF ENGINE POWER; AND THE PILOT'S FAILURE TO MAINTAIN SUFFICIENT AIRSPEED WHILE COPING WITH THE ENGINE PROBLEM, WHICH RESULTED IN A STALL. FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS, ICING CONDITIONS, AND ENGINE INLET (NACELLE) ICE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - light condition - dark night (contributing factor) - weather condition - icing conditions (contributing factor) - nacelle/pylon - ice (contributing factor) - Loss of engine power(total) - nonmechanical, approach - iaf to faf/outer marker (ifr) - all engines - procedures/directives - not followed, pilot in command (cause) - anti-ice/deice system - improper use of, pilot in command (cause) - Loss of control - in flight, descent - emergency - airspeed - not maintained, pilot in command (cause) - stall - inadvertent, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled ## Analysis N500AK ENCOUNTERED ICING IN FLIGHT BEFORE START OF ILS APPROACH. RADAR DATA SHOWED THAT BEFORE REACHING OUTER MARKER, IT SLOWED IN A MANNER THAT WAS CONSISTENT WITH A POWER REDUCTION (OR PARTIAL LOSS OF POWER), THEN IT ENTERED A STEEP DESCENT & CRASHED. EXAMINATION REVEALED ENGINES WERE NOT OPERATING AT IMPACT & THAT PROPELLERS HAD BEEN FEATHERED. NO PREIMPACT PART FAILURE OR MALFUNCTION OF ENGINES, PROPELLERS OR ANTI-ICE SYSTEM WAS FOUND. THERE WAS EVIDENCE THAT ENGINE INLET ANTI-ICE ANNUNCIATOR LIGHTS & STABILITY AUGMENTATION SYSTEM (SAS) FAULT WARNING LIGHT WERE ILLUMINATED DURING IMPACT. THE ENGINE MANUFACTURER REPORTED THAT FLAMEOUTS HAD OCCURRED IN OTHER AIRCRAFT, DURING OR FOLLOWING OPERATION IN ICING CONDITIONS, SOMETIMES AFTER DESCENT INTO WARMER AIR. FLIGHT MANUAL NOTED THAT IF ICING WAS ENCOUNTERED WITH ANTI-ICE SYSTEM OFF, SELECT CONTINUOUS IGNITION & THEN SELECT ENGINE & PROPELLER HEAT (1 ENGINE AT A TIME, ENSURING FIRST ENGINE WAS OPERATING SATISFACTORILY BEFORE SELECTING SECOND ENGINE) & ENGAGE SAS HEAT. ## Factual narrative HISTORY OF FLIGHT On April 1, 1993, at 2128 eastern standard time, a Fairchild Aircraft, SA227TT, N500AK, collided with the ground while executing an Instrument Landing System (ILS) approach to runway 23 at the Tri-City Regional Airport, Blountville, Tennessee. The registered owner was Robert H. Brooks, and the airplane was operated by Eastern Foods Inc.. The business flight was conducted under 14 CFR Part 91 with a valid instrument flight clearance. Visual weather conditions prevailed at the time of the accident. The airline transport rated pilot and three passengers were fatally injured, while the airplane was destroyed by impact forces and post impact fire. Origination of the flight was Knoxville, Tennessee, at 2100, on April 1, 1993. At 1421:53, a pilot who identified himself as the pilot of N500AK telephoned the Georgia Automated Flight Service Station (AFSS), Macon, Georgia, and stated that he planned a series of instrument flights from Fulton County Airport, Atlanta, Georgia. The pilot requested a weather briefing for the planned flights. According to the AFSS Air Traffic Control Specialist, the pilot was given a standard weather briefing, after which he filed four instrument flight plans (See the attached Eastern Foods flight schedule for April 1, 1993). Following two previous routine flights, N500AK arrived in the Knoxville area. At 1805, Atlanta Center, at the pilot's discretion, cleared the flight to descend to 11,000 feet from 16,000 feet. The pilot was advised to expect light to moderate icing during the descent. N500AK was handed off to Knoxville Approach for the approach and landing clearance at Knoxville, Tennessee. Upon landing at Knoxville, the airplane was serviced with 60 gallons of jet fuel. The pilot telephoned Nashville Flight Service Station and obtained a weather briefing. According to the Air Traffic Control Specialist, the pilot was given a standard weather briefing which included a pilot report of rime icing east of Knoxville. The pilot also confirmed that he had encountered icing conditions en route to Knoxville. At 2058, the flight was cleared for takeoff from Knoxville en route to Tri-City; the flight was subsequently assigned an en route altitude of 7000 feet. At 2110, Tri-City Approach accepted the flight as a radar handoff from Knoxville Approach Control; the pilot was advised to expect an ILS approach to Runway 23. Shortly after establishing contact with N500AK, approach control informed another aircraft of light icing reported by another aircraft at 10,000 feet (see attached witness statement from pilots of a Gulfstream, G-1 and a Beech, King Air). At 2128, N500AK was cleared to land. According to an Air Traffic Controller, he observed N500AK on final approach until it disappeared from view. He further stated that, while looking in the direction of landing traffic, he heard an unintelligible radio transmission from a pilot. At approximately the same time, the controller observed the lights of the airplane descend out of the bottom of the clouds. The lights appeared to have been in a steep spiraling descent. PERSONNEL INFORMATION Information on the pilot is included in this report at the data field labeled First Pilot Information. A review of the Federal Aviation Administration (FAA) records disclosed that the pilot had received an airframe and powerplant mechanic's certificate. The pilot was type rated in the Beech 400, Mitsubishi 400, Douglas DC-9 and the Fairchild SA227TT aircraft. The pilot completed his initial SA227TT training from Flight Safety International in February of 1992. According to Federal Aviation Administration records, the pilot received the SA227TT type rating from an FAA Operations Inspector assigned to the Saint Louis Flight Standards District Office on February 21, 1992. According to Eastern Foods Inc.,officials, the pilot was hired on January 27, 1992, as the company' principal pilot. The pilot's flight logs were not recovered for examination. Pilot flight time in the SA227TT shown in the pilot's information section is an estimate of flight time flown in N500AK since the pilot was hired. The total flight time was also secured from the company's personnel records. AIRCRAFT INFORMATION Information on the aircraft is contained in this report at the data fields labeled Aircraft Information. According to the Director Of Maintenance at Hill Aircraft & Leasing, Atlanta, Georgia, the pilot often requested assistance from Hill Aircraft to complete routine service and scheduled maintenance on N500AK. The following is a brief history of maintenance procedures performed on N500AK during the last two years: On June 9, 1991 at a total engine time of 1856.5 hours, 3,713 cycles, Garrett General Aviation Services Division Augusta, Georgia, performed major engine work (time since last inspection was 108.1 hours on both engines). On November 8, 1991 at a total engine time of 1946.8 hours, Hill Aircraft & Leasing performed Garrett Spectrographic Oil Analysis Program (SOAP) samples analysis and "A" & "B" inspections. On March 30, 1992 Hill Aircraft & Leasing performed Fairchild letter check program "C" and "D" at aircraft total time (ACTT) 2053.7 hours, time since hot section inspection (TSHSI) 197.2 hours, time since overhaul (TSO) 2035.4 hours. Fairchild Aircraft letter checks, "A" and "B", were performed at ACTT 2145.9 hours, TSHSI 289.4 hours TSO, 2127.6 Cycles 1778 by Hill Aircraft & Leasing Corp. The SOAP oil and filter analyses were completed with "normal" results. On February 2, 1992 at ACTT 2242.4 Fairchild letter check inspections "C" and "D" were performed by Hill Aircraft and Leasing, and Garrett SOAP analysis was carried out. On January 29, 1993 at ACTT 2293.8 and engine time 2280.1, cycles 1906, Garrett Aviation Services Division Augusta, GA cleaned and flow checked the fuel nozzles and rerigged both engines according to the Garrett maintenance manual. METEOROLOGICAL INFORMATION Visual weather conditions prevailed at the time of the accident. Weather information is contained in this report at the data field labeled Weather Information. The pilot received two weather briefings during the course of the days flight. Both Air Traffic Control Specialists alerted the pilot to the possibility of encountering inflight structural ice. According to the weather study, a trough of low pressure, in the lower atmosphere, was observed through central Kentucky, central Tennessee, and northern Alabama, at 1900 hours. A deep temperature trough centered over Missouri and northern Arkansas and prevailing westerly winds resulted in a low level, cold air advection, (the horizontal movement of an airmass associated with the change in temperature), across Tennessee, during the evening of April 1, 1993. The upper airstation at Nashville, Tennessee, was the closest site to Tri-city Airport. This site reported the freezing level, at 1900 hours, of less than 4000 feet. Further east, the upper air reporting site at Greensboro, North Carolina reported the freezing level at 7,500 feet at 1900 hours. The study also revealed that the bsae of the cloud layer was approximately 3900 feet and tops ranged in excess of 17000 feet. A pilot on final approach to Tri-City Regional Airport reported cloud bases at 4000 feet. WRECKAGE AND IMPACT INFORMATION The impact area was located in a pasture about 1/2 mile outside of the outer marker (North 36 degrees, 33 minutes, and 59 seconds by West 83 degrees, 19 minutes and 04 seconds). Examination of the accident site disclosed that the aircraft flight control surfaces were located in the immediate vicinity of the impact area. The center empennage sections of the airframe were fire damaged. Both engines were located in their respective positions, but the propeller assemblies separated from the propeller shafts and were buried about two feet into the ground. The wreckage came to rest on the downhill sid ## Aircraft - Registration: [N500AK](https://openairdocs.org/deregistered/N500AK-1993-10-06), registration cancelled 1993-10-06, S/N TT527 (OpenAirDocs) - Reported make and model: Fairchild SA227-TT - Registry model: [Swearingen SA227-TT](https://openairdocs.org/model/swearingen-sa227-tt) (registry code 8780620) (OpenAirDocs) - Category: Airplane - Serial number: TT-527 - Airframe hours: 2294 - Engines: Garrett TPE331-10U513 940 horsepower turbo prop - Damage: Destroyed - Fire: On-Ground - Flight: Executive/Corporate, Part 91 - Registered owner: Brooks, Robert H. - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, August 7, 1992, 50 hours before - Departed: TYS, KNOXVILLE, TN - Destination: TRI - Flight plan: IFR - Airport: TRI, Tri-City Regional, runway 23, 7,999 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 19,105 total, 235 in this make and model ## Weather - Conditions: Visual (VMC), Night/dark - Wind: 250° at 13 knots - Visibility: 6 statute miles - Lowest ceiling: 3,500 ft broken - Temperature: 46 °F, dew point 45 °F - Altimeter: 29.00 inHg - Observed at: TRI, 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 19930401007499A](https://openairdocs.org/incident/19930401007499A), Apr 1, 1993: Swrngn SA227TT, Bristol-Johnson, TN, Destroyed, 5 fatal. Approach in icing conditions. Lost control. Spiral dive to impact. Indicates engine icing flameouts. Airframe ice. 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.