An MD88 captain inadvertently hit the EPR lim button when he intended only to increase speed modestl...

Attributes
ACN	920553
Time
Date	201011
Local Time Of Day	1201-1800
Place
Locale Reference	D01.TRACON
State Reference	CO
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	Vectors SID Plains4
Flight Plan	IFR
Component
Aircraft Component	Throttle/Power Level
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 140 Flight Crew Total 18000 Flight Crew Type 9500
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Speed All Types

Narrative:

[I was] given a 280kt speed restriction and as aircraft leveled at 10000 feet (autopilot on); I went to select FMS override to only accelerate to 280K; but accidentally hit EPR lim button. Aircraft continued to accelerate and wanted to continue climb. Caught it by 10300 MSL after disconnecting autopilot; and subsequently the auto throttles; as aircraft accelerated to 335kts. Got situation under control and then re-established automation. ATC didn't query the slight and momentary altitude and airspeed deviation. The backlighting of all our MD88/90 flight guidance panels is frequently intermittent on various selector buttons for items such as FMS override; navigation; VNAV; alt hold; EPR lim; etc. If you lightly wiggle the button that's not lit often it will light up. However; you run the risk of selecting something you don't want to by doing this. I just plain hit the button next to the one I wanted; starting the cascading set of problems.

Original NASA ASRS Text

Title: An MD88 Captain inadvertently hit the EPR LIM button when he intended only to increase speed modestly in response to an ATC clearance. Before he could recover the aircraft deviated from both its altitude and airspeed clearance restraints.

Narrative: [I was] given a 280kt speed restriction and as aircraft leveled at 10000 feet (autopilot on); I went to select FMS override to only accelerate to 280K; but accidentally hit EPR LIM button. Aircraft continued to accelerate and wanted to continue climb. Caught it by 10300 MSL after disconnecting autopilot; and subsequently the auto throttles; as aircraft accelerated to 335kts. Got situation under control and then re-established automation. ATC didn't query the slight and momentary altitude and airspeed deviation. The backlighting of all our MD88/90 flight guidance panels is frequently intermittent on various selector buttons for items such as FMS override; NAV; VNAV; Alt Hold; EPR LIM; etc. If you lightly wiggle the button that's not lit often it will light up. However; you run the risk of selecting something you don't want to by doing this. I just plain hit the button next to the one I wanted; starting the cascading set of problems.

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.

An MD88 captain inadvertently hit the EPR lim button when he intended only to increase speed modestly in response to an ATC clearance. Before he could recover the aircraft deviated from both its altitude and airspeed clearance restraints.