The rapid climb and descent of FAST13 within 30 seconds exceeded the radar systems capability to accurately track and display the altitude changes. Accordingly, the air traffic controller providing services to TCF7530 and FAST13 did not observe FAST13 climb above the assigned altitude of FL280 nor did the controller receive a conflict alert from the radar system. The reason for FAST 13's deviation from assigned altitude was not determined. The TCAS onboard TCF7630 alerted as expected and the first officer appropriately initiated a climb in response to the RA. The seat belt sign was on prior to the TCAS alert because the flight attendants were preparing the cabin for landing. Shortly before the event, a passenger elected to go to the lavatory even though a flight attendant advised the passenger to return to his seat. The passenger was in the lavatory when the TCAS RA occurred resulting in him receiving a serious injury.
the abrupt maneuver that was appropriately initiated to comply with the TCAS resolution advisory caused by the momentary projected loss of separation from converging traffic. Contributing to the accident was a passenger's decision to disregard the seatbelt sign.
— 7,087 samples, 27 parameters, 11:32:40.0 to 11:35:34.9.
| Parameter | Max | at | Min | at | Final | at |
|---|---|---|---|---|---|---|
| Pitch attitude deg | 7.4 | 11:34:23.6 | -1.1 | 11:33:09.6 | 1.2 | 11:35:34.9 |
| Roll attitude deg | 2.5 | 11:35:17.6 | -6.5 | 11:34:50.1 | 0.7 | 11:35:34.6 |
| Vertical acceleration g | 2.4 | 11:34:23.5 | 0.5 | 11:34:24.8 | 1.1 | 11:35:34.9 |
| Time | Event | Page |
|---|---|---|
| about 11:33 CDT | Aircraft level at 29,000 ft for about 55 seconds before the alert | 4 |
| about 11:34 CDT | TCAS Combined Control = Climb Correction and TCAS Up Advisory = CLIMB, lasting about 11 seconds | 4 |
| +1 second | Autopilot Engaged transitioned to Not Engaged and the control column began moving aft; one second later AP Selected went to Not Selected and the column peaked at about 8 degrees aft, then moved forward to about -2 degrees a second later | 4 |
| evasive maneuver | Pitch oscillated from about 2 degrees before the event to 7, then 3, then 5, leveling at about 4 degrees; vertical acceleration increased to about 2.4 g, dropped to 0.5 g, then 1.25 g before settling; aircraft climbed to 29,600 ft | 4 |
| after the oscillations | TCAS Vertical Control indicated Increase for 6 seconds, ending with the other TCAS discretes | 4 |
Docket: data.ntsb.gov/Docket/?NTSBNumber=DCA10LA083. This brief is an analytical aid assembled from public records; it is not an investigative finding.