# NTSB CHI07LA252: Embraer EMB-145LR, N810HK, Knox, IN, August 7, 2007

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: August 7, 2007, 17:40 local (22:40 UTC)
- Place: Knox, IN
- Coordinates: 41.321945, -86.649169
- Nearby events: https://openairdocs.org/map.md?lat=41.3219&lon=-86.6492&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 38 uninjured
- Status: Completed, report August 28, 2008
- Report: Approved by Office Director
- Parties: O'Hare FSDO, Chicago, IL
- NTSB case key (mKey): 66457
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07LA252
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/66457/pdf
- Page: https://openairdocs.org/ntsb/CHI07LA252

## Probable cause

The in-flight encounter with turbulence.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, descent
  - weather condition - turbulence (cause)

## Analysis

The airplane encountered turbulence during descent flight which resulted in a serious injury to an unseated flight attendant.  The operator report stated that the flight attendant was returning to her jumpseat when the injury occurred. Flight data recorder data showed that the airplane experienced a vertical upset of 2.5 G's.

## Factual narrative

On August 7, 2007, about 1740 central daylight time, an Embraer EMB-145LR, N810HK, operated by Trans States Airlines, Inc., and piloted by an airline transport pilot, encountered turbulence while descending near Knox, Indiana.  The 14 CFR Part 121 passenger flight was operating on an instrument flight rules flight plan.  One flight attendant received serious injuries during the turbulence encounter.  No other injuries were reported.  The flight originated from the Roanoke Regional Airport, Raonoke, Virginia, at 1655 and was en route to the O'Hare International Airport, Chicago, Illinois.

According to the operator's report, the airplane encountered an area of severe turbulence.  The report further states that the flight attendant was injured as she was making her way to her jumpseat.  The flight attendant suffered a broken leg during the upset.

Plots of data obtained from the airplane's flight data recorder showed that the airplane experienced an vertical upset registering about 2.5 times the force of gravity.

## Aircraft

- Registration: N810HK (not matched to a registry record)
- Reported make and model: Embraer EMB-145LR
- Category: Airplane
- Serial number: 145231
- Airframe hours: 16112
- Engines: Rolls-Royce AE3007A1 7580 hp turbo fan; Rolls-Royce AE3007A1 7580 lbs thrust turbo fan
- Damage: No damage
- Flight: Part 121
- Registered owner: Trans States Airlines Inc
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, August 1, 2007
- Departed: ROA, ROANOKE, VA
- Destination: ORD, CHICAGO, IL
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review March 1, 2007; seat: left
- Co-pilot; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review April 1, 2007; seat: right

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 10 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 37 °F
- Altimeter: 29.77 inHg
- Observed at: ORD

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.

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