Captain of an large transport climbed suddenly to avoid WX without ATC clearance.

Attributes
ACN	304014
Time
Date	199502
Place
Locale Reference	atc facility : chs
State Reference	SC
Altitude	msl bound lower : 33000 msl bound upper : 34300
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zjx artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : atlantic enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 215 flight time total : 9600 flight time type : 1500
ASRS Report	304014
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : far non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

Captain was PF I was PNF. Aircraft was northbound on AR7 at FL330. There was a very narrow line of thunderstorms cutting across the airway running west to east. ZJX suggested deviating east to pick a hole to fly through but radar displayed weaker returns to our west. We received approval to deviate west as necessary then, to proceed direct ilm VOR. Tops of the thunderstorms were only about 1500 ft above us, but when I requested a climb to FL350 or block altitude of FL330-350 was denied by center. As we approached the WX, the captain without warning pitched up and climbed approximately 1300 ft as we went through the tops experiencing moderate turbulence, knocking down any flight attendants who happened to be standing in the back. As soon as I realized what captain was doing, I switched off mode C of transponder. We crossed WX within 10 seconds and captain then returned to FL330. ZJX said nothing to us and TCASII showed no traffic conflicts.

Original NASA ASRS Text

Title: CAPT OF AN LGT CLBED SUDDENLY TO AVOID WX WITHOUT ATC CLRNC.

Narrative: CAPT WAS PF I WAS PNF. ACFT WAS NBOUND ON AR7 AT FL330. THERE WAS A VERY NARROW LINE OF TSTMS CUTTING ACROSS THE AIRWAY RUNNING W TO E. ZJX SUGGESTED DEVIATING E TO PICK A HOLE TO FLY THROUGH BUT RADAR DISPLAYED WEAKER RETURNS TO OUR W. WE RECEIVED APPROVAL TO DEVIATE W AS NECESSARY THEN, TO PROCEED DIRECT ILM VOR. TOPS OF THE TSTMS WERE ONLY ABOUT 1500 FT ABOVE US, BUT WHEN I REQUESTED A CLB TO FL350 OR BLOCK ALT OF FL330-350 WAS DENIED BY CTR. AS WE APCHED THE WX, THE CAPT WITHOUT WARNING PITCHED UP AND CLBED APPROX 1300 FT AS WE WENT THROUGH THE TOPS EXPERIENCING MODERATE TURB, KNOCKING DOWN ANY FLT ATTENDANTS WHO HAPPENED TO BE STANDING IN THE BACK. AS SOON AS I REALIZED WHAT CAPT WAS DOING, I SWITCHED OFF MODE C OF XPONDER. WE CROSSED WX WITHIN 10 SECONDS AND CAPT THEN RETURNED TO FL330. ZJX SAID NOTHING TO US AND TCASII SHOWED NO TFC CONFLICTS.

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.