Flight instructor reported missing the log book entry for an inoperative oil temperature gauge that ...

Attributes
ACN	1755450
Time
Date	202008
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Component
Aircraft Component	Oil Temperature Indication
Person 1
Function	Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 130 Flight Crew Total 1474 Flight Crew Type 1015
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

Narrative:

91.205 VFR required equipment oil temperature gauge inoperative. Student did the pre-flight as I was running late to the flight school. I arrive and greet the owner of the flight school as they are getting ready to leave for the night. I tell them (the owners) I am going on a night flight tonight and they tell me to have a good flight. I do a briefing with my student on tonight's flight and we do a complete run-up not realizing the oil temp was inoperative. Once we reach ZZZ only do I realize that the oil temp has stayed in the same position the whole flight. We get back to our home airport and then I see the discrepancies booklet indicating the oil temperature gauge has been noted.I failed to check the discrepancies booklet before the flight and continued the flight anyways. The owners of the flight school have known of the issue before my flight and failed to notify me of the issue. They continued to fly the aircraft today not fixing the issue.

Original NASA ASRS Text

Title: Flight Instructor reported missing the log book entry for an inoperative oil temperature gauge that was required equipment for night VFR training flight and conducting the flight.

Narrative: 91.205 VFR required equipment oil temperature gauge inoperative. Student did the pre-flight as I was running late to the flight school. I arrive and greet the owner of the flight school as they are getting ready to leave for the night. I tell them (the owners) I am going on a night flight tonight and they tell me to have a good flight. I do a briefing with my student on tonight's flight and we do a complete run-up not realizing the oil temp was inoperative. Once we reach ZZZ only do I realize that the oil temp has stayed in the same position the whole flight. We get back to our home airport and then I see the Discrepancies booklet indicating the oil temperature gauge has been noted.I failed to check the discrepancies booklet before the flight and continued the flight anyways. The owners of the flight school have known of the issue before my flight and failed to notify me of the issue. They continued to fly the aircraft today not fixing the issue.

Data retrieved from NASA's ASRS site 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.

Flight instructor reported missing the log book entry for an inoperative oil temperature gauge that was required equipment for night VFR training flight and conducting the flight.