Small aircraft pilot departs SVFR after sunset.

Attributes
ACN	194089
Time
Date	199111
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : osh
State Reference	WI
Altitude	agl bound lower : 500 agl bound upper : 1000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tower : osh
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : initial climbout : takeoff
Route In Use	approach : svfr
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 17800 flight time type : 350
ASRS Report	194089
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	other anomaly other
Independent Detector	other other : unspecified cockpit
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Osh had snow showers off and on during the afternoon. I checked the WX every hour or 2. I received my pre-departure briefing by wxmation, destination was VFR. Removed all snow from the aircraft and monitored ATIS. WX was M 27 overcast 1 southwest. Upon taxi out and SVFR clearance request it was 7 overcast 1 1/2 southwest (I think information XXX). SVFR clearance was received. Takeoff was to the east and turnout to the northeast. The SVFR conditions were localized and conditions improved after takeoff. The flight to mtw was VFR and AWOS at mtw was no clouds below 12000 and 3 1/2 mi upon arrival. Very light snow was the restriction to visibility. My concern: I may have departed after sunset at osh, SVFR. My question: if this was the case, why isn't it the policy of the tower (if he was aware of it) to advise me the same. Sometimes the obvious is overlooked and a little hint from an outside source turns the light on! Lack of communication can be a killer, as we learn in cockpit resource management. The final decision is with the PIC but outside help, both in the cockpit (even from the passenger in my private airplane) or ATC is welcomed by me and I think should be policy by ATC when obvious.

Original NASA ASRS Text

Title: SMA PLT DEPARTS SVFR AFTER SUNSET.

Narrative: OSH HAD SNOW SHOWERS OFF AND ON DURING THE AFTERNOON. I CHKED THE WX EVERY HR OR 2. I RECEIVED MY PRE-DEP BRIEFING BY WXMATION, DEST WAS VFR. REMOVED ALL SNOW FROM THE ACFT AND MONITORED ATIS. WX WAS M 27 OVERCAST 1 SW. UPON TAXI OUT AND SVFR CLRNC REQUEST IT WAS 7 OVERCAST 1 1/2 SW (I THINK INFO XXX). SVFR CLRNC WAS RECEIVED. TKOF WAS TO THE EAST AND TURNOUT TO THE NE. THE SVFR CONDITIONS WERE LOCALIZED AND CONDITIONS IMPROVED AFTER TKOF. THE FLT TO MTW WAS VFR AND AWOS AT MTW WAS NO CLOUDS BELOW 12000 AND 3 1/2 MI UPON ARR. VERY LIGHT SNOW WAS THE RESTRICTION TO VISIBILITY. MY CONCERN: I MAY HAVE DEPARTED AFTER SUNSET AT OSH, SVFR. MY QUESTION: IF THIS WAS THE CASE, WHY ISN'T IT THE POLICY OF THE TWR (IF HE WAS AWARE OF IT) TO ADVISE ME THE SAME. SOMETIMES THE OBVIOUS IS OVERLOOKED AND A LITTLE HINT FROM AN OUTSIDE SOURCE TURNS THE LIGHT ON! LACK OF COM CAN BE A KILLER, AS WE LEARN IN COCKPIT RESOURCE MGMNT. THE FINAL DECISION IS WITH THE PIC BUT OUTSIDE HELP, BOTH IN THE COCKPIT (EVEN FROM THE PAX IN MY PRIVATE AIRPLANE) OR ATC IS WELCOMED BY ME AND I THINK SHOULD BE POLICY BY ATC WHEN OBVIOUS.

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.