Ptk tower reported IMC conditions but a flight crew was able to see the airport at about 4 miles and...

Narrative:

On descent to ptk I received the ATIS and the weather had improved to 2 miles from 1 1/4 miles. We also had ground contact and forward visibility of at least 3-4 miles. I asked approach to vector us in close so as to maybe get the visual. The approach they would have vectored us for was past the airport. We called the airport in sight and ATC cleared us for a visual approach. We landed without incident. After post-flight I received a call from the tower instructing me that the field was actually IFR and that I was given an illegal clearance. He suggested I should have asked for a contact approach or executed the 27L B/C approach. I said I actually thought the field was VFR based on my forward visibility; forgetting about the last ATIS. I did not tell him that we were not authorized to conduct 'contact approaches'. He said the call was more for informational purposes; but the approach controller was going to file an as soon as possible.due to the fact I had good VFR visibility; I accepted the visual approach when the ATIS/tower was still reporting IFR conditions. I did not have the company's 3 mile restriction and should have conducted the approach procedure or get an updated visibility report.

Original NASA ASRS Text

Title: PTK Tower reported IMC conditions but a flight crew was able to see the airport at about 4 miles and reqested a visual approach but was then advised after landing that the clearance was not legal.

Narrative: On descent to PTK I received the ATIS and the weather had improved to 2 miles from 1 1/4 miles. We also had ground contact and forward visibility of at least 3-4 miles. I asked Approach to vector us in close so as to maybe get the visual. The approach they would have vectored us for was past the airport. We called the airport in sight and ATC cleared us for a Visual approach. We landed without incident. After post-flight I received a call from the Tower instructing me that the field was actually IFR and that I was given an illegal clearance. He suggested I should have asked for a contact approach or executed the 27L B/C approach. I said I actually thought the field was VFR based on my forward visibility; forgetting about the last ATIS. I did not tell him that we were not authorized to conduct 'contact approaches'. He said the call was more for informational purposes; but the Approach Controller was going to file an ASAP.Due to the fact I had good VFR visibility; I accepted the visual approach when the ATIS/Tower was still reporting IFR conditions. I did not have the company's 3 mile restriction and should have conducted the approach procedure or get an updated visibility report.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1116943
Time
Date	201309
Local Time Of Day	0601-1200
Place
Locale Reference	D21.TRACON
State Reference	MI
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Beechcraft / Beech Aircraft Corp Undifferentiated or Other Model
Operating Under FAR Part	Part 135
Flight Phase	Initial Approach
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural FAR Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

Ptk tower reported IMC conditions but a flight crew was able to see the airport at about 4 miles and reqested a visual approach but was then advised after landing that the clearance was not legal.