Atx small aircraft encounters extreme turbulence and microburst on approach to land.

Attributes
ACN	261513
Time
Date	199401
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : chs
State Reference	SC
Altitude	msl bound lower : 1600 msl bound upper : 2300
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : chs
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 135
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 60 flight time total : 2300 flight time type : 280
ASRS Report	261513
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	inflight encounter : weather other anomaly other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Autoplt unable to hold altitude (climb indicated), while airspeed began to increase into the yellow arc. Advancing warm front producing supercooled rain below 3000 ft overcast with a 50 KT headwind and a full 1 inch pressure drop within the last 50 mi reported by ATC for altimeter setting. Encountered a cloud which produced violent turbulence about all 3 axes. Nothing had shown on stormscope prior nor had previous cloud encounters produced this effect. 180 degrees to east initiated with vectors back to charleston for the VOR DME #3 approach. Stratus at 600 ft and heavy rain reduced visibility further as microburst enveloped aircraft. Gear down, throttles idle and airspeed is still in the yellow arc. As we approached 800 ft and unable to hold minimum approach altitude, power was restored to full despite high airspeed in continuing violent turbulence. 100 FPM climb was attained up to 1000 ft as ATC vectored aircraft direct to runway 3 as cockpit navigational instruments were unreadable in the turbulence. Despite accepting clearance for VOR approach, the aircraft was unable to hold the assigned altitude of 1600 ft in the downblast. The aircraft landed with no further problems.

Original NASA ASRS Text

Title: ATX SMA ENCOUNTERS EXTREME TURB AND MICROBURST ON APCH TO LAND.

Narrative: AUTOPLT UNABLE TO HOLD ALT (CLB INDICATED), WHILE AIRSPD BEGAN TO INCREASE INTO THE YELLOW ARC. ADVANCING WARM FRONT PRODUCING SUPERCOOLED RAIN BELOW 3000 FT OVCST WITH A 50 KT HEADWIND AND A FULL 1 INCH PRESSURE DROP WITHIN THE LAST 50 MI RPTED BY ATC FOR ALTIMETER SETTING. ENCOUNTERED A CLOUD WHICH PRODUCED VIOLENT TURB ABOUT ALL 3 AXES. NOTHING HAD SHOWN ON STORMSCOPE PRIOR NOR HAD PREVIOUS CLOUD ENCOUNTERS PRODUCED THIS EFFECT. 180 DEGS TO E INITIATED WITH VECTORS BACK TO CHARLESTON FOR THE VOR DME #3 APCH. STRATUS AT 600 FT AND HVY RAIN REDUCED VISIBILITY FURTHER AS MICROBURST ENVELOPED ACFT. GEAR DOWN, THROTTLES IDLE AND AIRSPD IS STILL IN THE YELLOW ARC. AS WE APCHED 800 FT AND UNABLE TO HOLD MINIMUM APCH ALT, PWR WAS RESTORED TO FULL DESPITE HIGH AIRSPD IN CONTINUING VIOLENT TURB. 100 FPM CLB WAS ATTAINED UP TO 1000 FT AS ATC VECTORED ACFT DIRECT TO RWY 3 AS COCKPIT NAVIGATIONAL INSTS WERE UNREADABLE IN THE TURB. DESPITE ACCEPTING CLRNC FOR VOR APCH, THE ACFT WAS UNABLE TO HOLD THE ASSIGNED ALT OF 1600 FT IN THE DOWNBLAST. THE ACFT LANDED WITH NO FURTHER PROBS.

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.