Flight crew turns without clearance to avoid WX encounter.

Attributes
ACN	293330
Time
Date	199501
Day	Sat
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : mia
State Reference	FL
Aircraft 1
Controlling Facilities	artcc : zma tracon : cuuz
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	293330
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
ASRS Report	293194
Events
Anomaly	inflight encounter : weather non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On the arrival from the northwest into miami, a cold front was passing through the miami area. About 90 mi from the airport we were slowed to 250 KTS and vectored sbound for sequencing to mia. On a 180 degree heading about 80 mi west of the airport, we had to deviate because of a cell we were starting to enter. ATC was quite busy and we had to make an immediate turn. I told the first officer that when he could get a word in, to tell ATC that we were turning left to a 120 degree heading to stay clear of the WX. It took approximately 40 seconds to get through to ATC and let them know our heading. I know they were very busy but we had to deviate at that moment. The reason we did not call them earlier to deviate was due to the radar return. However, as we entered the heavier area of rain and turbulence, it was obvious that we needed to turn and get out of it.

Original NASA ASRS Text

Title: FLC TURNS WITHOUT CLRNC TO AVOID WX ENCOUNTER.

Narrative: ON THE ARR FROM THE NW INTO MIAMI, A COLD FRONT WAS PASSING THROUGH THE MIAMI AREA. ABOUT 90 MI FROM THE ARPT WE WERE SLOWED TO 250 KTS AND VECTORED SBOUND FOR SEQUENCING TO MIA. ON A 180 DEG HDG ABOUT 80 MI W OF THE ARPT, WE HAD TO DEVIATE BECAUSE OF A CELL WE WERE STARTING TO ENTER. ATC WAS QUITE BUSY AND WE HAD TO MAKE AN IMMEDIATE TURN. I TOLD THE FO THAT WHEN HE COULD GET A WORD IN, TO TELL ATC THAT WE WERE TURNING L TO A 120 DEG HDG TO STAY CLR OF THE WX. IT TOOK APPROX 40 SECONDS TO GET THROUGH TO ATC AND LET THEM KNOW OUR HDG. I KNOW THEY WERE VERY BUSY BUT WE HAD TO DEVIATE AT THAT MOMENT. THE REASON WE DID NOT CALL THEM EARLIER TO DEVIATE WAS DUE TO THE RADAR RETURN. HOWEVER, AS WE ENTERED THE HEAVIER AREA OF RAIN AND TURB, IT WAS OBVIOUS THAT WE NEEDED TO TURN AND GET OUT OF IT.

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.