A300 first officer reports a sudden pitch over passing an airspace fix on a STAR; causing the speed ...

Narrative:

We were on arrival into ZZZ. Autopilot was on and profile was engaged. Cost index was set to standard prior to descent. After passing [an airspace fix] at 210 knots and approximately 9;100 feet; the aircraft abruptly pitched nose down and speed increased to approximately 225-230 knots. I quickly selected 8;000 feet in the altitude preset window (required at or above altitude at [the intersection]) and level change on the fcp and the aircraft quickly slowed to 210 knots. Total time of speed exceedance was about 7-10 seconds. The remainder of the arrival was flown uneventfully in level change. While light turbulence could have played a small role; I am not sure why the aircraft pitched down so abruptly causing the speed increase. All altitude restrictions were 'comfortably' made. I have not seen this scenario before; but after discussions with other airbus crewmembers; I learned that they have seen similar behavior at nearly the same point on this arrival.

Original NASA ASRS Text

Title: A300 First Officer reports a sudden pitch over passing an airspace fix on a STAR; causing the speed to increase to 230 knots from 210 knots. Other A300 crews have reported similar anomalies at the same location.

Narrative: We were on arrival into ZZZ. Autopilot was on and Profile was engaged. Cost index was set to standard prior to descent. After passing [an airspace fix] at 210 knots and approximately 9;100 feet; the aircraft abruptly pitched nose down and speed increased to approximately 225-230 knots. I quickly selected 8;000 feet in the altitude preset window (required at or above altitude at [the intersection]) and Level Change on the FCP and the aircraft quickly slowed to 210 knots. Total time of speed exceedance was about 7-10 seconds. The remainder of the arrival was flown uneventfully in Level Change. While light turbulence could have played a small role; I am not sure why the aircraft pitched down so abruptly causing the speed increase. All altitude restrictions were 'comfortably' made. I have not seen this scenario before; but after discussions with other Airbus crewmembers; I learned that they have seen similar behavior at nearly the same point on this arrival.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1089838
Time
Date	201305
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	A300
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence

A300 first officer reports a sudden pitch over passing an airspace fix on a STAR; causing the speed to increase to 230 knots from 210 knots. Other A300 crews have reported similar anomalies at the same location.