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Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database

EMBRAER ERJ 170-100 LR — Chicago, IL, USA, 2024-09-25

NTSB number
DCA24LA318
Operator
Envoy Air Inc.
Registration
N772MR
Highest injury
No injury
Regulation
Part 121
Damage
—
Cohort
Part 121 airline
Recorder data
Tier 1 — decoded recorder tables
Every sentence below is taken directly from NTSB records — the accident database, the docket's recorder reports and the Board's findings — with its source noted. Nothing is paraphrased or inferred.

NTSB summary

This incident occurred when the flight crew of Envoy Airlines flight 3936 (ENY3936), an Embraer 170-100 LR, was cleared for a visual approach to land on runway 10C at Chicago O’Hare International Airport (ORD), Chicago, Illinois, however, the flight crew inadvertently landed on runway 10L. While on descent and upon initial check-in with the ORD approach controller, the flight crew was instructed to expect runway 10C. They were subsequently cleared for the instrument landing system (ILS) to runway 10C. The flight crew acknowledged and correctly read back the approach clearance. The flight crew stated that the captain, who was the pilot monitoring, briefed the approach, programmed the flight management computer (FMC) with the ILS approach to runway 10C to back up the planned visual approach. However, they were not receiving the ILS identifier. The captain attempted to troubleshoot why the localizer frequency would not autotune by reloading the approach in the FMC and manually tuning the frequency. Unable to resolve the issue they elected to proceed visually. The captain contacted the air traffic control tower (ATCT) controller stating they were on the visual approach to runway 10C, and the airplane was cleared to land on runway 10C. However, the airplane was aligned with and landed on runway 10L. The flight crew’s decision to continue the approach without the correct ILS frequency was likely affected by their task saturation and planned continuation bias, and their inability to perceive and efficiently integrate available information. Planned continuation bias is an unconscious cognitive phenomenon to continue with the original plan in spite of changing conditions. Once a plan is made and committed to, it becomes increasingly difficult for stimuli or changing conditions to be recognized as necessitating a change to the plan. In addition, as workload increases conditions that may appear obvious to individuals external to the situation are difficult for people caught up in the plan to recognize. Recorded data from the flight data recorder revealed that while flying a heading to intercept the ILS 10C, the localizer frequency in the Nav 1 radio was correctly tuned to 108.95 MHz, the frequency for the ILS 10C localizer, for four seconds. Subsequently, the Nav 1 radio was changed to 108.4 MHz and Nav 2 radio was changed to 113.0 MHz for the remainder of the flight. Although the correct ILS frequency (108.95 MHz) was briefly tuned in the Nav 1 radio, it was subsequently changed to an incorrect frequency (108.4 MHz), and Nav 2 was tuned to a non-ILS frequency (113.0 MHz), preventing the crew from confirming alignment with runway 10C. The FAA mandatory occurrence report (MOR) revealed that the ATCT controller noticed the runway alignment error and coordinated with the runway 10L controller to allow ENY3936 to land on the incorrect runway as no traffic conflicts were noted. The air traffic control (ATC) services provided by the controller were deficient and contrary to FAA directives. Specifically, the controller failed to notify ENY3936 of their alignment error and did not issue control instructions to prevent the wrong surface landing. Had the controller notified the flight crew of the alignment error or provided control instructions it is likely that the wrong surface landing would have been prevented.
Verbatim, NTSB aviation accident database (narratives.narr_accf).

Probable cause

The flight crew’s misidentification of the intended landing runway, which resulted in an approach to and landing on the wrong runway due to their planned continuation bias. Contributing to the incident was the flight crew’s decision to continue the approach without the correct ILS frequency in the FMS. Also contributing was air traffic control’s failure to notify the flight crew that the were lined up with the incorrect runway contrary to FAA directives.
Verbatim, NTSB determination.

Flight data recorder

Universal CVFDR · N772MR — 16,590 samples, 23 parameters, 15:14:00.1 to 15:27:59.9.

ParameterMaxatMinatFinalat
Ground speed kts297.015:14:00.733.015:27:59.733.015:27:59.7
Computed from the docket's tabular attachment; times as recorded (local or SRN as published).

Sequence of events (FDR factual report)

TimeEventPage
15:14:09 CDTThe aircraft was descending through 10,000 feet (ft) at 249 knots (kts) calibrated airspeed. The autopilot was engaged. The vertical and lateral modes were flight level change (FLCH) and lateral navigation (LNAV), respectively. Nav1 and Nav2 selected frequencies were 114.2 Megahertz (MHz) and 113.0 MHz, respectively.5
15:15:50 CDTThe aircraft was at pressure altitude of 7,032 ft at 248 kts calibrated airspeed. The vertical and lateral modes were altitude hold (ALT HOLD) and LNAV, respectively. Nav1 selected frequency was changed to 108.4 MHz.5
15:17:50 CDTNav2 selected frequency was changed to 108.4 MHz.5
15:18:14 CDTNav2 selected frequency was changed to 113.0 MHz.5
15:19:30 CDTThe active lateral mode changed from LNAV to heading (HDG).5
15:19:54 CDTNav1 and Nav2 selected frequencies were changed to 108.95 MHz and 108.4 MHz, respectively.6
15:19:55 CDTThe glideslope and localizer deviation-1 were 1.4866 dots and -2.8352 dots, respectively, for one second before both changed back to 0 dots.6
15:19:58 CDTNav1 selected frequency was changed to 108.4 MHz and remained at this frequency for the remainder of the flight.6
15:20:26 CDTNav2 selected frequency was changed to 113.0 MHz and remained at this frequency for the remainder of the flight.6
15:21:08 CDTThe captain selected primary navigation changed from FMS1 to VOR/LOC1. One second later, the first officer's primary navigation changed from FMS2 to VOR/LOC2, where both remained for the remainder of the flight.6
15:22:54 CDTThe autopilot was disengaged.6
15:26:25 CDTThe aircraft landed on runway 10L at KORD.6
Extracted by claude-sonnet-5; 12 of 12 stated events verified against the raw recorder data.

Recorder documents in the docket

GroupTitlePagesType
fdrFLIGHT DATA RECORDER - SPECIALIST'S FACTUAL REPORT14pdf
fdrFLIGHT DATA RECORDER - SPECIALIST'S FACTUAL REPORT - ATTACHMENT1 - EVENT TABULAR DATAcsv
fdrFLIGHT DATA RECORDER - SPECIALIST'S FACTUAL REPORT - ATTACHMENT2 - SECOND FLIGHT TABULAR DATAcsv

Docket: data.ntsb.gov/Docket/?NTSBNumber=DCA24LA318. This brief is an analytical aid assembled from public records; it is not an investigative finding.