Embraer S A EMB-545 N179SP accident near Houston, Texas

Probable cause

The crew failed to ensure the main entry door was locked before departure. Contributing to the accident was a corroded/jammed door sensor that provided an erroneous locked indication to the crew alerting system.

NTSB analysis

The two pilots departed on a business flight with two passengers and observed that the airplane did not pressurize during the initial climb out. As the climb continued, the crew observed a door open warning on the crew alerting system (CAS). The pilot in command (PIC), seated in the right seat, got out of his seat to check the door and attempted to push the handle down toward the locked position, but stated that “it kept coming up.” About 14 seconds after the PIC got out of his seat, the main cabin door opened inflight, which resulted in substantial damage to the door and fuselage. The PIC returned to his seat and commented several times that the second in command (SIC) had not secured the door. The flight returned to land without further incident.

Postaccident examination revealed no anomalies that would have prevented the door from a normal sequence of closing, latching, and locking. A corroded/jammed locked sensor assembly was observed that erroneously indicated a locked door to the CAS when the door was actually only latched but not locked. However, the two visual locked indications on the door functioned properly, which was consistent with the crew not fully closing the door or observing the unsafe (red) visual locked indicators.

During climb out, the aerodynamic forces on the door and/or airplane vibration likely caused the target for closed door sensor to move away from the sensor, which triggered the CAS door open warning. The aerodynamic forces on the door, airplane vibration, and/or the PIC’s handle movement likely allowed the door to open inflight.

Text from the NTSB. Open the NTSB docket for CEN23LA003 for the full record.