# NTSB CEN21LA388: Cessna 172, N6778A, Iron Mountain, MI, August 3, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: August 3, 2021, 11:30 local (16:30 UTC) - Place: Iron Mountain, MI · on the ramp - Coordinates: 45.818361, -88.114556 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.8184&lon=-88.1146&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi: Prop/jet/rotor blast/suction](https://openairdocs.org/ntsb-events/082) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Flight Standards District Office, Skywest Airlines - NTSB case key (mKey): 103772 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA388 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103772/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103772 - Page: https://openairdocs.org/ntsb/CEN21LA388 ## Probable cause The mechanics’ failure to follow procedures for high-thrust operations at the nontowered airport, which resulted in jet blast damage to an airplane taxiing nearby. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Info processing/decision: understanding/comprehension](https://openairdocs.org/ntsb-findings/02041515): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Cessna 172, 1 case](https://openairdocs.org/ntsb-findings/02041515/cases.md?model=2072402), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/02041515/cases.md) - [Knowledge: knowledge of procedures](https://openairdocs.org/ntsb-findings/02032010): Personnel issues › Experience/knowledge · Maintenance personnel (probable cause); cases with it: [Cessna 172, 1 case](https://openairdocs.org/ntsb-findings/02032010/cases.md?model=2072402), [All aircraft, 41 cases](https://openairdocs.org/ntsb-findings/02032010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi: Prop/jet/rotor blast/suction](https://openairdocs.org/ntsb-events/082) (defining event); cases with it: [Cessna 172, 2 cases](https://openairdocs.org/ntsb-events/082/sequence.md?model=2072402), [All aircraft, 44 cases](https://openairdocs.org/ntsb-events/082/sequence.md) ## Analysis The pilot landed the Cessna 172 at the nontowered airport and taxied toward parking. As the Cessna 172 passed about 200 ft behind a Bombardier CRJ-200 parked on the ramp, two mechanics onboard the CRJ-200 were conducting a maintenance test and were not aware of the Cessna 172. The mechanics increased the CRJ-200’s engine power, and jet blast lifted the Cessna 172’s tail, which resulted in the Cessna 172 nosing down and sustaining substantial damage to the left wing. The mechanics did not follow several of the operator’s procedures for high-thrust maintenance operations at a nontowered airport, including notifying airport management personnel of high-thrust operations, selecting the most appropriate location on the airport, and actively communicating high-thrust intentions on the airport’s common traffic advisory frequency. Their failure to follow these procedures led to their performing high-thrust operations near a taxiing airplane. ## Factual narrative On August 3, 2021, about 1130 central daylight time, a Cessna 172, N6778A, was substantially damaged when it was involved in an accident at Ford Airport (IMT), Iron Mountain, Michigan. The pilot and passenger suffered minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported he landed at IMT, a nontowered airport, and taxied toward parking. As the pilot passed about 200 ft behind a parked Bombardier CRJ-200, he noted that cones were placed around the CRJ-200 and the airplane’s beacon was rotating, but no marshal or spotter was on the ramp. Two mechanics were conducting a maintenance test on the CRJ-200 and were not aware of the taxiing Cessna 172. The mechanics did not announce an intention on the airport’s common traffic advisory frequency to increase engine power. After engine power was increased, jet blast lifted the Cessna 172’s tail, which resulted in the Cessna 172 nosing down and sustaining substantial damage to the left wing when it contacted the ground. The mechanics did not comply with the operator’s procedures for high-thrust maintenance operations at a non-towered airport. The procedures included notification of airport management personnel of high-thrust operations, selecting the most appropriate location on the airport, and actively communicating intentions on the airport’s common traffic advisory frequency. Following the accident, the operator reinforced training and communications to mechanics on the risks of high-thrust maintenance operations at nontowered airports. ## Aircraft - Registration: [N6778A](https://openairdocs.org/aircraft/N6778A), registered now, S/N 28878, built 1956 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna 172](https://openairdocs.org/model/cessna-172) (registry code 2072402) (OpenAirDocs) - Registry engine: [Continental 0-300 series](https://openairdocs.org/engine/continental-0-300-series) (registry code 17022, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28878 - Year built: 1956 - Airframe hours: 2502 - Engines: CONT MOTOR 0-300 SER 145 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 15, 2021 - Departed: IMT, Iron Mountain, MI - Airport: IMT, Ford ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 28; injuries: minor; airline transport; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review June 21, 2021; seat: left; restraint: 4-point; flight hours: 7,109 total, 425 in this make and model, 2,902 as pilot in command, 220 in the last 90 days, 64 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 4 knots - Visibility: 10 statute miles - Temperature: 75 °F, dew point 63 °F - Altimeter: 29.99 inHg - Observed at: KIMT - METAR: KIMT 241654Z AUTO 20004KT 10SM FEW021 24/17 A2999 ## Docket (4 files) The files NTSB released with the investigation on December 15, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103772. 5.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 5.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13632602&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photo of airplane (item 2, PDF, 1 page, 216 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13632331&FileExtension=pdf&FileName=Photo-Rel.pdf - Correspondence with airport manager (item 3, PDF, 1 page, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13632518&FileExtension=pdf&FileName=Airport%20manager%20-%20memo%20to%20FAA_Redacted-Rel.pdf - Correspondence with operator (item 4, PDF, 2 pages, 212 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13632811&FileExtension=pdf&FileName=Operator%20Correspondence_Redacted-Rel.pdf 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.