B737-800 captain reported his flying first officer experienced an overspeed on descent.

Attributes
ACN	976260
Time
Date	201110
Local Time Of Day	1201-1800
Place
Locale Reference	ZNY.ARTCC
State Reference	NY
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Published Material / Policy Deviation - Speed All Types

Narrative:

I was the pilot not flying. During descent and while going through the descent checklist I felt the aircraft turn and pitch down aggressively. I noticed the airspeed increasing and called out 'airspeed'. The first officer initially tried to shallow out the descent by using vertical speed and speed brakes to stop the airspeed from increasing further. The speed brakes actually caused the aircraft to momentarily pitch down more which resulted in the overspeed warning to briefly sound.

Original NASA ASRS Text

Title: B737-800 Captain reported his flying First Officer experienced an overspeed on descent.

Narrative: I was the pilot not flying. During descent and while going through the descent checklist I felt the aircraft turn and pitch down aggressively. I noticed the airspeed increasing and called out 'airspeed'. The First Officer initially tried to shallow out the descent by using vertical speed and speed brakes to stop the airspeed from increasing further. The speed brakes actually caused the aircraft to momentarily pitch down more which resulted in the overspeed warning to briefly sound.

Data retrieved from NASA's ASRS site as of April 2012 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.