# Incident 19990915034139I: Boeing 737522, Denver, CO, September 15, 1999

- Type: FAA incident report (Accident/Incident Data System), as reported
- Date: September 15, 1999, 08:20 local time
- Place: Denver, CO
- Phase of flight: Final Approach-IFR
- Operating rules: Air carrier (Part 121)
- Operator: UALA
- Location: 39.7392° N, 104.9847° W: Placed by OpenAirDocs: center of Denver, CO, within about 7 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=39.7392&lon=-104.9847&mi=10
- Aircraft: N954UA, a cancelled registration (https://openairdocs.org/deregistered/N954UA-2005-06-30) (OpenAirDocs)
- Registry model: Boeing 737-522 (registry code 138449F, https://openairdocs.org/model/boeing-737-522) (OpenAirDocs)
- Registry engine: CFM International CFM56 series (registry code 13802, https://openairdocs.org/engine/cfm-international-cfm56-series) (OpenAirDocs)
- Reported make and model: BOEING 737522
- Pilot flight hours: 14,800 total, 2,138 in this make and model, 204 in the last 90 days
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19990915034139I

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

(-23) ON 9/15/99, UALA FLT 1253 EXPERIENCED POSSIBLE UNCOMMANDED RUDDER DEFLECTION DURING VISUAL APPROACH, FIRST OFFICER (F/O) FLYING, TO RWY 35L AT DENVER (DEN), 3 TO 4 MILES BEHIND ANOTHER B-737, AND WAS CLEARED TO LAND 35L. AT APPROX. DYMON (FINAL APPROACH FIX), AIRCRAFT ENCOUNTERED MOMENTARY WAKE TURBULENCE, THEN SMOOTH AIR. THE AIRCRAFT THEN ROLLED TO THE RIGHT.  F/O APPLIED LEFT AILERON AND THE AIRCRAFT BEGAN TO RESPOND AND THEN AGAIN BEGAN TO ROLL FURTHER RIGHT TO APPROX. 30 DEGREES.  F/O APPLIED FULL LEFT RUDDER.  AIRCRAFT DID NOT RESPOND FOR SEVERAL SECONDS.  THE CAPTAIN CALLED FOR A GO AROUND AND THE AIRCRAFT RESPONDED.  THE AIRCRAFT RETURNED TO RWY 35R AND LANDED WITHOUT FURTHER INCIDENT.  F/O STATED HE FELT THE RIGHT RUDDER TRAVEL 1/4 TO 1/2 OF FULL DEFLECTION UNCOMMANDED.  UALA MAINTENANCE AT DENVER ACCOMPLISHED ENGINEERING CALLOUTS, CH7268, RUDDER PCU SERVO VALVE TEST, AND CH7266, YAW DAMPER TROUBLE SHOOTING.  NO DEFECTS WERE NOTED.  AIRCRAFT WAS RETURNED TO SERVICE 9/16/99.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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