Commuter light transport exceeded mmo during descent.

Attributes
ACN	161237
Time
Date	199010
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : vrb
State Reference	FL
Altitude	msl bound lower : 10000 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute airway : y295
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4200 flight time type : 950
ASRS Report	161237
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	non adherence : far other anomaly
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After beginning a descent from FL180 to 10000' MSL, the mmo limit was exceeded inadvertently by approximately 5 KTS. This was caused by inadequate autoplt management allowing the aircraft to descend at too great a rate for the power selected. The first officer either did not notice this or chose not to say anything about this until the airspeed limit had been exceeded. Power was reduced slightly to decrease speed below the mmo limit and in the interim time period (about 1 min) the aural warning circuit breaker was pulled to silence the warning. Poor flight supervision was demonstrated in allowing the airspeed to build to this pint and poor judgement was exercised in pulling the circuit breaker to silence the warning. Although the aircraft was probably not placed in a hazardous position since the speed excess was so small, my actions could be interpreted by my first officer as being ok and not unusual. This could lead to future problems with this (or any other in a similar position) first officer by not demonstrating the proper respect for aircraft limitations now,and allowing him to upgrade the captain with the thought that the limitations can be exceeded and the warning systems disabled at will.

Original NASA ASRS Text

Title: COMMUTER LTT EXCEEDED MMO DURING DESCENT.

Narrative: AFTER BEGINNING A DSNT FROM FL180 TO 10000' MSL, THE MMO LIMIT WAS EXCEEDED INADVERTENTLY BY APPROX 5 KTS. THIS WAS CAUSED BY INADEQUATE AUTOPLT MGMNT ALLOWING THE ACFT TO DSND AT TOO GREAT A RATE FOR THE PWR SELECTED. THE F/O EITHER DID NOT NOTICE THIS OR CHOSE NOT TO SAY ANYTHING ABOUT THIS UNTIL THE AIRSPD LIMIT HAD BEEN EXCEEDED. PWR WAS REDUCED SLIGHTLY TO DECREASE SPD BELOW THE MMO LIMIT AND IN THE INTERIM TIME PERIOD (ABOUT 1 MIN) THE AURAL WARNING CB WAS PULLED TO SILENCE THE WARNING. POOR FLT SUPERVISION WAS DEMONSTRATED IN ALLOWING THE AIRSPD TO BUILD TO THIS PINT AND POOR JUDGEMENT WAS EXERCISED IN PULLING THE CB TO SILENCE THE WARNING. ALTHOUGH THE ACFT WAS PROBABLY NOT PLACED IN A HAZARDOUS POS SINCE THE SPD EXCESS WAS SO SMALL, MY ACTIONS COULD BE INTERPRETED BY MY F/O AS BEING OK AND NOT UNUSUAL. THIS COULD LEAD TO FUTURE PROBS WITH THIS (OR ANY OTHER IN A SIMILAR POS) F/O BY NOT DEMONSTRATING THE PROPER RESPECT FOR ACFT LIMITATIONS NOW,AND ALLOWING HIM TO UPGRADE THE CAPT WITH THE THOUGHT THAT THE LIMITATIONS CAN BE EXCEEDED AND THE WARNING SYSTEMS DISABLED AT WILL.

Data retrieved from NASA's ASRS site as of July 2007 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.