LJ25 crew, during climb, overshot assigned altitude.

Attributes
ACN	499928
Time
Date	200101
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zob.artcc
State Reference	OH
Altitude	msl bound lower : 27000 msl bound upper : 27600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air taxi
Make Model Name	Learjet 25
Operating Under FAR Part	Part 135
Flight Phase	climbout : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : atp
Experience	controller military : 10 controller non radar : 13 controller radar : 13 flight time total : 2540
ASRS Report	499928
Person 2
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	controller military : 10 controller non radar : 39 controller radar : 37 flight time last 90 days : 150 flight time total : 22000 flight time type : 810
ASRS Report	499920
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Altitude warning system failed, and we overshot our assigned altitude (FL270) by 600 ft. There were no obvious causes, including switches or circuit breakers. A system test yielded an intermittent tone, and the 'off' flag remained visible. During the climb, however, there was no aural warning. On jan/xa/01, maintenance discovered that the cannon plug had loosened, and they tightened the connection, resulting in apparently normal operation.

Original NASA ASRS Text

Title: LJ25 CREW, DURING CLB, OVERSHOT ASSIGNED ALT.

Narrative: ALT WARNING SYS FAILED, AND WE OVERSHOT OUR ASSIGNED ALT (FL270) BY 600 FT. THERE WERE NO OBVIOUS CAUSES, INCLUDING SWITCHES OR CIRCUIT BREAKERS. A SYS TEST YIELDED AN INTERMITTENT TONE, AND THE 'OFF' FLAG REMAINED VISIBLE. DURING THE CLB, HOWEVER, THERE WAS NO AURAL WARNING. ON JAN/XA/01, MAINT DISCOVERED THAT THE CANNON PLUG HAD LOOSENED, AND THEY TIGHTENED THE CONNECTION, RESULTING IN APPARENTLY NORMAL OP.

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.