Narrative:

During this potion of cruise flight; the aircraft experienced moderate turbulence. We reduced the speed to that appropriate to turbulent air penetration and switched to continuous ignition. The captain was on his scheduled break and I was the acting PIC. Shortly we encountered (or the turbulence led the autoplt to artificially create) wave action. It began a light; but about the sixth 'parabola' had become moderate or greater. Our ivsi modulated between an 1800 FPM climb and 1800 FPM descent. Our IAS; between 10 KTS below vmo/mmo and about 10 KTS below green DOT; a spread of close to 40 KTS. It was then that I disconnected both autoplt and autothrust and brought the aircraft back to straight and level. I then reconnected both autoplt and autothrust. Light to moderate turbulence continued; but the wave action had ceased. This is why I believe that the aircraft had created or significantly contributed to its own wave effect. The flight continued without further incident; but our exceedance report was generated by the printer. Observation and opinion: 1) the airbus software package should include a program to dampen self-induced wave action. 2) we should receive training on proper recover techniques. 3) I had reacted; in part; to thrust inputs which modulated from flight idle to the tla (thrust lever angle); but there is no indication; that we had a thrust management problem. At least initially I should have left the autothrust engaged and disconnected only the autoplt. My mistake. It created more work in an already difficult situation. 4) I should have turned up the EFIS background lights at the start of the event. Screens that are easy to read in smooth; straight and level flight become very difficult to observe in moderate turbulence and wave action. Adjusting the screens while hand flying is; of course; impossible. Callback conversation with reporter revealed the following information: reporter stated that he still believes the aircraft continued in self induced oscillations because of how rapidly the oscillations ceased after the autoplt and autothrust were removed. He stated the turbulence did not end but the aircraft's apparent wave motion did cease following his actions. During a discussion about possible rvsm TCAS warnings; the reporter stated that a TCAS warning was not a concern at their particular location. However the reporter stated that he talked with a captain who had experienced a similar event and a TCAS reaction was required.

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Original NASA ASRS Text

Title: AN A330 PLT DESCRIBES A WAVE ACTION EVENT WITH MODERATE TURB AND AN AIRSPD EXCEEDANCE.

Narrative: DURING THIS POTION OF CRUISE FLT; THE ACFT EXPERIENCED MODERATE TURB. WE REDUCED THE SPD TO THAT APPROPRIATE TO TURBULENT AIR PENETRATION AND SWITCHED TO CONTINUOUS IGNITION. THE CAPT WAS ON HIS SCHEDULED BREAK AND I WAS THE ACTING PIC. SHORTLY WE ENCOUNTERED (OR THE TURB LED THE AUTOPLT TO ARTIFICIALLY CREATE) WAVE ACTION. IT BEGAN A LIGHT; BUT ABOUT THE SIXTH 'PARABOLA' HAD BECOME MODERATE OR GREATER. OUR IVSI MODULATED BTWN AN 1800 FPM CLB AND 1800 FPM DSCNT. OUR IAS; BTWN 10 KTS BELOW VMO/MMO AND ABOUT 10 KTS BELOW GREEN DOT; A SPREAD OF CLOSE TO 40 KTS. IT WAS THEN THAT I DISCONNECTED BOTH AUTOPLT AND AUTOTHRUST AND BROUGHT THE ACFT BACK TO STRAIGHT AND LEVEL. I THEN RECONNECTED BOTH AUTOPLT AND AUTOTHRUST. LIGHT TO MODERATE TURB CONTINUED; BUT THE WAVE ACTION HAD CEASED. THIS IS WHY I BELIEVE THAT THE ACFT HAD CREATED OR SIGNIFICANTLY CONTRIBUTED TO ITS OWN WAVE EFFECT. THE FLT CONTINUED WITHOUT FURTHER INCIDENT; BUT OUR EXCEEDANCE RPT WAS GENERATED BY THE PRINTER. OBSERVATION AND OPINION: 1) THE AIRBUS SOFTWARE PACKAGE SHOULD INCLUDE A PROGRAM TO DAMPEN SELF-INDUCED WAVE ACTION. 2) WE SHOULD RECEIVE TRAINING ON PROPER RECOVER TECHNIQUES. 3) I HAD REACTED; IN PART; TO THRUST INPUTS WHICH MODULATED FROM FLT IDLE TO THE TLA (THRUST LEVER ANGLE); BUT THERE IS NO INDICATION; THAT WE HAD A THRUST MGMNT PROB. AT LEAST INITIALLY I SHOULD HAVE LEFT THE AUTOTHRUST ENGAGED AND DISCONNECTED ONLY THE AUTOPLT. MY MISTAKE. IT CREATED MORE WORK IN AN ALREADY DIFFICULT SITUATION. 4) I SHOULD HAVE TURNED UP THE EFIS BACKGROUND LIGHTS AT THE START OF THE EVENT. SCREENS THAT ARE EASY TO READ IN SMOOTH; STRAIGHT AND LEVEL FLT BECOME VERY DIFFICULT TO OBSERVE IN MODERATE TURB AND WAVE ACTION. ADJUSTING THE SCREENS WHILE HAND FLYING IS; OF COURSE; IMPOSSIBLE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE STILL BELIEVES THE ACFT CONTINUED IN SELF INDUCED OSCILLATIONS BECAUSE OF HOW RAPIDLY THE OSCILLATIONS CEASED AFTER THE AUTOPLT AND AUTOTHRUST WERE REMOVED. HE STATED THE TURB DID NOT END BUT THE ACFT'S APPARENT WAVE MOTION DID CEASE FOLLOWING HIS ACTIONS. DURING A DISCUSSION ABOUT POSSIBLE RVSM TCAS WARNINGS; THE RPTR STATED THAT A TCAS WARNING WAS NOT A CONCERN AT THEIR PARTICULAR LOCATION. HOWEVER THE RPTR STATED THAT HE TALKED WITH A CAPT WHO HAD EXPERIENCED A SIMILAR EVENT AND A TCAS REACTION WAS REQUIRED.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.