Atx helicopter enters IMC after descending to avoid. Declares emergency, requested ASR approach.

Attributes
ACN	206822
Time
Date	199204
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : crp
State Reference	TX
Altitude	msl bound lower : 200 msl bound upper : 500
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : crp
Operator	common carrier : air taxi
Make Model Name	Helicopter
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 75 flight time total : 7600 flight time type : 100
ASRS Report	206822
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	inflight encounter : vfr in imc other anomaly other
Independent Detector	other other : unspecified cockpit
Resolutory Action	controller : issued new clearance flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Weather

Narrative:

While returning to my base from an offshore location in predominant VMC (1000-1500 ft overcast, 5-7 mi visibility, scattered rain showers). I suddenly encountered fog. I descended from 500 ft MSL to 300 ft MSL, then momentarily to 200 ft MSL in an attempt to get beneath what I thought was a shallow stratus layer. I next attempted a 180 degree climbing turn but found myself above 300 ft MSL in solid overcast approximately 2.8 NM from my LORAN indicated destination. Within the preceding 15 mins, 3 company aircraft had departed the same general area in VMC. I was surprised by the rapid change in flight conditions. Company aircraft to my northeast were reporting ceilings of 1300-1500 ft MSL. I continued my outbound climb to 1500 ft MSL without breaking out -- at that point, I declared an emergency to corpus christi approach control and requested an ASR approach into corpus christi naval air station. I was given an ASR approach to VMC (400 ft MSL) where I resumed VFR flight to my destination. I was in an area of rapidly changing meteorological conditions for which I was unprepared (based upon forecasts, in-flight observation and expected conditions). Had I reacted 30 seconds to 1 min earlier, it is possible I would have regained VMC conditions. At the point that I declared an emergency to ATC, I was exercising what I considered to be my last available option.

Original NASA ASRS Text

Title: ATX HELI ENTERS IMC AFTER DSNDING TO AVOID. DECLARES EMER, REQUESTED ASR APCH.

Narrative: WHILE RETURNING TO MY BASE FROM AN OFFSHORE LOCATION IN PREDOMINANT VMC (1000-1500 FT OVCST, 5-7 MI VISIBILITY, SCATTERED RAIN SHOWERS). I SUDDENLY ENCOUNTERED FOG. I DSNDED FROM 500 FT MSL TO 300 FT MSL, THEN MOMENTARILY TO 200 FT MSL IN AN ATTEMPT TO GET BENEATH WHAT I THOUGHT WAS A SHALLOW STRATUS LAYER. I NEXT ATTEMPTED A 180 DEG CLBING TURN BUT FOUND MYSELF ABOVE 300 FT MSL IN SOLID OVCST APPROX 2.8 NM FROM MY LORAN INDICATED DEST. WITHIN THE PRECEDING 15 MINS, 3 COMPANY ACFT HAD DEPARTED THE SAME GENERAL AREA IN VMC. I WAS SURPRISED BY THE RAPID CHANGE IN FLT CONDITIONS. COMPANY ACFT TO MY NE WERE RPTING CEILINGS OF 1300-1500 FT MSL. I CONTINUED MY OUTBOUND CLB TO 1500 FT MSL WITHOUT BREAKING OUT -- AT THAT POINT, I DECLARED AN EMER TO CORPUS CHRISTI APCH CTL AND REQUESTED AN ASR APCH INTO CORPUS CHRISTI NAVAL AIR STATION. I WAS GIVEN AN ASR APCH TO VMC (400 FT MSL) WHERE I RESUMED VFR FLT TO MY DEST. I WAS IN AN AREA OF RAPIDLY CHANGING METEOROLOGICAL CONDITIONS FOR WHICH I WAS UNPREPARED (BASED UPON FORECASTS, INFLT OBSERVATION AND EXPECTED CONDITIONS). HAD I REACTED 30 SECONDS TO 1 MIN EARLIER, IT IS POSSIBLE I WOULD HAVE REGAINED VMC CONDITIONS. AT THE POINT THAT I DECLARED AN EMER TO ATC, I WAS EXERCISING WHAT I CONSIDERED TO BE MY LAST AVAILABLE OPTION.

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.