# NTSB MIA97IA151: Beech 100, N402G, Kenly, NC, April 5, 1997 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: April 5, 1997, 10:30 local (15:30 UTC) - Place: Kenly, NC - Coordinates: 35.589851, -78.120384 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.5899&lon=-78.1204&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 29, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 38161 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA97IA151 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/38161/pdf - Page: https://openairdocs.org/ntsb/MIA97IA151 ## Probable cause Inadequate inspection procedures by the airframe manufacturer for failure to require removal of the metal retaining ring to inspect the entire area of the window for cracks. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, climb - to cruise - window,flight compartment window/windshield - failure,total - condition(s)/step(s) not listed, manufacturer (cause) - window,flight compartment window/windshield - cracked ## Analysis About 15 minutes after departure while climbing through 12,000 to 12,500 feet, at a cabin differential pressure of 4.3 psi, the pilot's flight compartment side 'D' window separated with a resulting rapid decompression. The pilot diverted to the destination airport and landed uneventfully. Post incident examination of the failed window revealed evidence of preexisting cracks that originated at the external surface of the window at the transition radius between the window flange and the center portion of the window. The failed window had accumulated 4,008 hours since replacement at failure and was the latest design. Review of the inspection requirements for the window which is scheduled to occur every 600 hours revealed that the metal retaining ring is not required to be removed for inspection. ## Factual narrative On April 5, 1997, about 1030 eastern standard time, a Beech 100, N402G, registered to and operated by ISO Aero Service, Inc., experienced failure of the pilot's "D" oversize window while climbing to cruise near Kenly, North Carolina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 positioning flight. The airplane sustained minor damage and the airline transport-rated pilot, the sole occupant, was not injured. The flight originated about 15 minutes earlier from the Kinston Regional Jetport at Stallings Field, Kinston, North Carolina. The pilot stated that while climbing through 12,000 for 12,500 feet, at a cabin differential pressure of 4.3 psi, the pilot's flight compartment side "D" window separated. He diverted to his departure airport and landed uneventfully. At the time of the window separation the cabin altitude was about 2,000 feet. The remaining portion of the failed window was sent to the NTSB Materials Laboratory in Washington, D.C. Examination of the window revealed evidence of preexisting cracks that originated at the external surface of the window at the transition radius between the window flange and the center portion of the window. Review of the maintenance records for the airplane revealed that the failed window was installed on February 13, 1986, in accordance with an Airworthiness Directive. At the time of failure, the airplane had accumulated 4,008 hours since the window installation. Further review of the maintenance records revealed that it was last inspected on October 10, 1996. The airplane had accumulated about 240 hours since that inspection at the time of failure. The airframe manufacturer inspection requirements for the failed window does not require the removal of the metal retaining ring to examine the entire area of the window for cracks if none are visually observed on the outer surface of the window during the initial inspection. Additionally, a detailed inspection of the failed window is required by the manufacturer to be accomplished only every 600 hours. ## Aircraft - Registration: [N402G](https://openairdocs.org/deregistered/N402G-2001-08-17), registration cancelled 2001-08-17, S/N B-14 (OpenAirDocs) - Reported make and model: Beech 100 - Registry model: [Beech 100](https://openairdocs.org/model/beech-100) (registry code 1152916) (OpenAirDocs) - Category: Airplane - Serial number: B-14 - Airframe hours: 9758 - Engines: P&W PT6-28 680 horsepower turbo prop - Damage: Minor damage - Flight: Positioning, Part 91 - Registered owner: Iso Aero Service, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, January 9, 1997, 76 hours before - Departed: ISO, KINSTON, NC - Destination: GSO, GREENSBORO, NC ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 10,000 total, 3,000 in this make and model, 9,000 as pilot in command, 75 in the last 90 days, 15 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 5 knots - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 50 °F - Altimeter: 30.00 inHg - Observed at: ISO ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 19970405014689I](https://openairdocs.org/incident/19970405014689I), Apr 5, 1997: Beech 100BEECH, Kinston, NC, Minor damage. Narrative: on Saturday, April 5, 1997, king air 100, N402G, operated by iso aero svc., kingston, NC departed winston, NC on an IFR flight plan. While passing… 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.