19990915034139I

Incident

FAA incident report · Boeing 737-522 · Denver, CO · September 15, 1999

Date: September 15, 1999 · 08:20 local
Place: Denver, CO
Phase of flight: Final Approach-IFR
Operating rules: Air carrier (Part 121)
Operator: UALA
Aircraft: N954UA
Reported as: Boeing 737522
Pilot’s flight hours: 14,800 total2,138 in this make and model204 in the last 90 days

N954UARegistration cancelled Jun 30, 2005 · Boeing 737-522S/N 26739 · Built 1993 Airframe modelBoeing 737-522 Engine modelCFM International CFM56 seriesTurbo-fan

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry 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.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

(-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.

As the FAA filed it

(-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.