A319 crew encounters mountain wave; which causes aircraft to climb 600 feet and exceed vmo by 10 KTS...

Attributes
ACN	733051
Time
Date	200703
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : bld.vortac
State Reference	NV
Altitude	msl bound lower : 39000 msl bound upper : 39600
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	A319
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise : level
Route In Use	arrival star : maier
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 225 flight time total : 14700 flight time type : 1600
ASRS Report	733051
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 20400 flight time type : 4200
ASRS Report	733052
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather other anomaly other anomaly
Independent Detector	aircraft equipment other aircraft equipment : overspeed warning other flight crewa other flight crewb
Resolutory Action	flight crew : returned to assigned altitude flight crew : regained aircraft control
Supplementary
Problem Areas	Weather Aircraft
Primary Problem	Weather

Narrative:

At FL390; in smooth air; cruising at .79 mach; we got into a mountain wave and the airspeed increased 20 KTS within just a few seconds. The airspeed increased into the barber pole by 10 KTS. At this point; the aircraft's overspd protection feature took over and started climbing the aircraft. I had selected a slower speed and put the speed brakes out to slow the aircraft. There is no way to override this overspd protection. We went up to FL396 before I regained control of the aircraft. We descended back down to FL390 and reported the change of altitude and mountain wave to ATC. I don't see how we could have done anything differently or changed anything to improve the situation. Supplemental information from acn 733052: strong mountain wave encountered at FL390; aircraft's maximum certificated ceiling was exceeded by 600 ft and vmo exceeded by 10 KTS. (Airbus aircraft automatically protect themselves by pitching up in overspd situations.) the mountain wave causes the airspeed exceedance and the built-in protective features of airbus's automation caused the altitude exceedance.

Original NASA ASRS Text

Title: A319 CREW ENCOUNTERS MOUNTAIN WAVE; WHICH CAUSES ACFT TO CLIMB 600 FEET AND EXCEED VMO BY 10 KTS.

Narrative: AT FL390; IN SMOOTH AIR; CRUISING AT .79 MACH; WE GOT INTO A MOUNTAIN WAVE AND THE AIRSPD INCREASED 20 KTS WITHIN JUST A FEW SECONDS. THE AIRSPD INCREASED INTO THE BARBER POLE BY 10 KTS. AT THIS POINT; THE ACFT'S OVERSPD PROTECTION FEATURE TOOK OVER AND STARTED CLBING THE ACFT. I HAD SELECTED A SLOWER SPD AND PUT THE SPD BRAKES OUT TO SLOW THE ACFT. THERE IS NO WAY TO OVERRIDE THIS OVERSPD PROTECTION. WE WENT UP TO FL396 BEFORE I REGAINED CTL OF THE ACFT. WE DSNDED BACK DOWN TO FL390 AND RPTED THE CHANGE OF ALT AND MOUNTAIN WAVE TO ATC. I DON'T SEE HOW WE COULD HAVE DONE ANYTHING DIFFERENTLY OR CHANGED ANYTHING TO IMPROVE THE SITUATION. SUPPLEMENTAL INFO FROM ACN 733052: STRONG MOUNTAIN WAVE ENCOUNTERED AT FL390; ACFT'S MAX CERTIFICATED CEILING WAS EXCEEDED BY 600 FT AND VMO EXCEEDED BY 10 KTS. (AIRBUS ACFT AUTOMATICALLY PROTECT THEMSELVES BY PITCHING UP IN OVERSPD SITUATIONS.) THE MOUNTAIN WAVE CAUSES THE AIRSPD EXCEEDANCE AND THE BUILT-IN PROTECTIVE FEATURES OF AIRBUS'S AUTOMATION CAUSED THE ALT EXCEEDANCE.

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.