A CRJ200 captain reported confusion in the cockpit as to who was flying the aircraft led to an altit...

Narrative:

During the cruise phase of flight we were given a crossing restriction. The instructions were to cross at 26;000 ft at a DME fix that was south of the VOR. The first officer was flying. When he began the descent he accidentally depressed the toga button; which is located on the thrust lever. This resulted in the autopilot being disconnected. The first officer heard the autopilot disconnect alarm; but thought that I disconnected the autopilot. He did not realize that he had accidentally disconnected it. I reached up and silenced the alarm and he interpreted the autopilot disconnect and me silencing the alarm as me having taken over the controls. I never announced that I had taken control of the aircraft. He then used the vertical speed scroll wheel to select down; which resulted in pitch mode instead of vertical speed mode due to the toga function having accidentally been selected. The aircraft pitched down quickly. I attempted to talk and mentor him out of the flight condition however he thought I had assumed control of the aircraft and he was not making control inputs. I did not realize that he was no longer flying until we reached our assigned altitude and I instructed the first officer to level off and he didn't. I assumed the controls however; we were already through our assigned altitude. We returned as expeditiously as we safely could. No resolution advisories were received.

Original NASA ASRS Text

Title: A CRJ200 Captain reported confusion in the cockpit as to who was flying the aircraft led to an altitude deviation.

Narrative: During the cruise phase of flight we were given a crossing restriction. The instructions were to cross at 26;000 FT at a DME fix that was south of the VOR. The First Officer was flying. When he began the descent he accidentally depressed the TOGA button; which is located on the thrust lever. This resulted in the autopilot being disconnected. The First Officer heard the autopilot disconnect alarm; but thought that I disconnected the autopilot. He did not realize that he had accidentally disconnected it. I reached up and silenced the alarm and he interpreted the autopilot disconnect and me silencing the alarm as me having taken over the controls. I never announced that I had taken control of the aircraft. He then used the vertical speed scroll wheel to select down; which resulted in pitch mode instead of vertical speed mode due to the TOGA function having accidentally been selected. The aircraft pitched down quickly. I attempted to talk and mentor him out of the flight condition however he thought I had assumed control of the aircraft and he was not making control inputs. I did not realize that he was no longer flying until we reached our assigned altitude and I instructed the First Officer to level off and he didn't. I assumed the controls however; we were already through our assigned altitude. We returned as expeditiously as we safely could. No resolution advisories were received.

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.

Attributes
ACN	850641
Time
Date	200909
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 250 Flight Crew Total 4800 Flight Crew Type 3500
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance

A CRJ200 captain reported confusion in the cockpit as to who was flying the aircraft led to an altitude deviation.