An air carrier medium large transport was flown in an unairworthy condition.

Attributes
ACN	277081
Time
Date	199407
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	ground : preflight other
Route In Use	enroute airway : zzz
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 160 flight time total : 5000 flight time type : 1250
ASRS Report	277081
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 80 flight time total : 9000 flight time type : 1500
ASRS Report	277231
Events
Anomaly	aircraft equipment problem : critical non adherence : far other anomaly other
Independent Detector	other other : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other
Situations
Publication	Unspecified

Narrative:

We operated an aircraft deemed airworthy by maintenance, but was unairworthy by the FAA. Pitot heat #3 was placarded inoperative -- technician thought the light bulb was inoperative but in fact the pitot heat was inoperative. We flew the aircraft all day not knowing the airplane was unairworthy. Aircraft maintenance was unaware that the airplane was unairworthy. We finally were notified a week later by our assistant chief pilot that maintenance called the FAA and admitted their fault by releasing the aircraft as airworthy, when in fact, the airplane should have been grounded.

Original NASA ASRS Text

Title: AN ACR MLG WAS FLOWN IN AN UNAIRWORTHY CONDITION.

Narrative: WE OPERATED AN ACFT DEEMED AIRWORTHY BY MAINT, BUT WAS UNAIRWORTHY BY THE FAA. PITOT HEAT #3 WAS PLACARDED INOP -- TECHNICIAN THOUGHT THE LIGHT BULB WAS INOP BUT IN FACT THE PITOT HEAT WAS INOP. WE FLEW THE ACFT ALL DAY NOT KNOWING THE AIRPLANE WAS UNAIRWORTHY. ACFT MAINT WAS UNAWARE THAT THE AIRPLANE WAS UNAIRWORTHY. WE FINALLY WERE NOTIFIED A WK LATER BY OUR ASSISTANT CHIEF PLT THAT MAINT CALLED THE FAA AND ADMITTED THEIR FAULT BY RELEASING THE ACFT AS AIRWORTHY, WHEN IN FACT, THE AIRPLANE SHOULD HAVE BEEN GNDED.

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.