What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Narrative: while in cruise flight at 35,000' MSL, at mach .745, first officer walter was flying N673AA on an inbound course to avenal VOR. Approximately thirty (30) minutes into the flight, captain stated N673AA felt as they encountered wake turbulence followed immediately by an uncommanded, but non-violent, roll to the right, to approximately 20 to 25 degree bank. The aircraft lost approximately 300' altitude while first officer and captain attempted to regain full control of N673AA. Captain duke assumed command, checked TCAS display for traffic, manually disengaged the selected "b" system auto-pilot with sounding of subsequent auto-pilot aural warning, applied 1/4 left rudder input, and brought wings level. He stated with auto-pilot disconnected, he gained more left aileron control. Estimated time duration from uncommamded roll, back to wings level, was twenty (20) seconds. No other cockpit aural warnings were heard during the occurrence. With wings level, the control yoke was approximately 35 degrees, left aileron down. Without flight crew's control input, both captain and first officer estimated N673AA would have rolled inverted within ten (10) seconds from initiation of uncommanded roll. First officer walter reported full right rudder indication and commenced a memorized quick reference handbook (qrh) procedure and requested to disconnect the yaw damper system. Captain confirmed and ordered yaw damper be disconnected. Upon yaw damper disconnect, control yoke returned to 0 degrees, wings remained level, and rudder returned to center. Due to altitude restrictions with yaw damper inoperative, first officer requested a descent to 28,000' MSL. When ATC could not provide immediate clearance, captain immediately requested descent vectors to 28,000' MSL. ATC responded by vectoring N673AA be quarantined pending further investigation. The NTSB, Washington DC has control of this investigation and has coordinated with swaa to have the removed component tested. Larry smith, AAI-100 is the FAA poc. If findings are released to this office, we will amend this report.
As the FAA filed it
NARRATIVE: WHILE IN CRUISE FLIGHT AT 35,000' MSL, AT MACH .745, FIRST OFFICER WALTER WAS FLYING N673AA ON AN INBOUND COURSE TO AVENAL VOR. APPROXIMATELY THIRTY (30) MINUTES INTO THE FLIGHT, CAPTAIN STATED N673AA FELT AS THEY ENCOUNTERED WAKE TURBULENCE FOLLOWED IMMEDIATELY BY AN UNCOMMANDED, BUT NON-VIOLENT, ROLL TO THE RIGHT, TO APPROXIMATELY 20 TO 25 DEGREE BANK. THE AIRCRAFT LOST APPROXIMATELY 300' ALTITUDE WHILE FIRST OFFICER AND CAPTAIN ATTEMPTED TO REGAIN FULL CONTROL OF N673AA. CAPTAIN DUKE ASSUMED COMMAND, CHECKED TCAS DISPLAY FOR TRAFFIC, MANUALLY DISENGAGED THE SELECTED "B" SYSTEM AUTO-PILOT WITH SOUNDING OF SUBSEQUENT AUTO-PILOT AURAL WARNING, APPLIED 1/4 LEFT RUDDER INPUT, AND BROUGHT WINGS LEVEL. HE STATED WITH AUTO-PILOT DISCONNECTED, HE GAINED MORE LEFT AILERON CONTROL. ESTIMATED TIME DURATION FROM UNCOMMAMDED ROLL, BACK TO WINGS LEVEL, WAS TWENTY (20) SECONDS. NO OTHER COCKPIT AURAL WARNINGS WERE HEARD DURING THE OCCURRENCE. WITH WINGS LEVEL, THE CONTROL YOKE WAS APPROXIMATELY 35 DEGREES, LEFT AILERON DOWN. WITHOUT FLIGHT CREW'S CONTROL INPUT, BOTH CAPTAIN AND FIRST OFFICER ESTIMATED N673AA WOULD HAVE ROLLED INVERTED WITHIN TEN (10) SECONDS FROM INITIATION OF UNCOMMANDED ROLL. FIRST OFFICER WALTER REPORTED FULL RIGHT RUDDER INDICATION AND COMMENCED A MEMORIZED QUICK REFERENCE HANDBOOK (QRH) PROCEDURE AND REQUESTED TO DISCONNECT THE YAW DAMPER SYSTEM. CAPTAIN CONFIRMED AND ORDERED YAW DAMPER BE DISCONNECTED. UPON YAW DAMPER DISCONNECT, CONTROL YOKE RETURNED TO 0 DEGREES, WINGS REMAINED LEVEL, AND RUDDER RETURNED TO CENTER. DUE TO ALTITUDE RESTRICTIONS WITH YAW DAMPER INOPERATIVE, FIRST OFFICER REQUESTED A DESCENT TO 28,000' MSL. WHEN ATC COULD NOT PROVIDE IMMEDIATE CLEARANCE, CAPTAIN IMMEDIATELY REQUESTED DESCENT VECTORS TO 28,000' MSL. ATC RESPONDED BY VECTORING N673AA BE QUARANTINED PENDING FURTHER INVESTIGATION. THE NTSB, WASHINGTON DC HAS CONTROL OF THIS INVESTIGATION AND HAS COORDINATED WITH SWAA TO HAVE THE REMOVED COMPONENT TESTED. LARRY SMITH, AAI-100 IS THE FAA POC. IF FINDINGS ARE RELEASED TO THIS OFFICE, WE WILL AMEND THIS REPORT.
Other reports on N673AA · 1
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