Company maintenance personnel illegally deferred an item on the minimum equipment list.

Attributes
ACN	128592
Time
Date	198911
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hpn
State Reference	NY
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	ground : preflight
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : cfi pilot : atp
Experience	flight time last 90 days : 240 flight time total : 2200 flight time type : 300
ASRS Report	128592
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : far non adherence other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

An item that is on the mdt MEL (and a spoiler retract switch) was illegally MEL'd by our airline's maintenance control. 3 other crews flew the aircraft thinking that the switch was properly MEL'd. (All parties were at fault.) the switch had to be operational for the aircraft to fly. Since I was the first officer, I took my captain's word that the aircraft was legal to fly.

Original NASA ASRS Text

Title: COMPANY MAINTENANCE PERSONNEL ILLEGALLY DEFERRED AN ITEM ON THE MINIMUM EQUIPMENT LIST.

Narrative: AN ITEM THAT IS ON THE MDT MEL (AND A SPOILER RETRACT SWITCH) WAS ILLEGALLY MEL'D BY OUR AIRLINE'S MAINT CTL. 3 OTHER CREWS FLEW THE ACFT THINKING THAT THE SWITCH WAS PROPERLY MEL'D. (ALL PARTIES WERE AT FAULT.) THE SWITCH HAD TO BE OPERATIONAL FOR THE ACFT TO FLY. SINCE I WAS THE F/O, I TOOK MY CAPT'S WORD THAT THE ACFT WAS LEGAL TO FLY.

Data retrieved from NASA's ASRS site as of August 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.