Updraft causes widebody transport to climb above assigned altitude.

Attributes
ACN	179667
Time
Date	199106
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw
State Reference	TX
Altitude	msl bound lower : 11000 msl bound upper : 11800
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : commercial pilot : atp pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 0 flight time total : 3500
ASRS Report	179667
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : military
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While on a 295 degree heading from dfw approach control, approximately 5 mi from the airport at 11000' assigned, we encountered an abrupt updraft associated with a thunderstorm (approximately 15-20 mi away) that sent the aircraft up 500', knocking the autoplt off. We climbed almost to 12000' before a correction was initiated. There was a very slight delay in recovery as the copilot momentarily looked at the above field level (afl) altimeter. A smooth recovery to 11000' was made. I do not think the deviation could have been avoided, but the recovery could have begun sooner. The confusion caused the copilot to look at the wrong altimeter--air carrier uses QFE and qnh. The copilot flies jets in the military reserves, and when flustered, reverted to his military training by looking at the altimeter on his instrument panel. I have flown with the QFE, qnh system for 11 yrs and amused to it, but I think it has outlived its usefulness now that there are radar altimeters to give AGL information.

Original NASA ASRS Text

Title: UPDRAFT CAUSES WDB TO CLIMB ABOVE ASSIGNED ALT.

Narrative: WHILE ON A 295 DEG HDG FROM DFW APCH CTL, APPROX 5 MI FROM THE ARPT AT 11000' ASSIGNED, WE ENCOUNTERED AN ABRUPT UPDRAFT ASSOCIATED WITH A TSTM (APPROX 15-20 MI AWAY) THAT SENT THE ACFT UP 500', KNOCKING THE AUTOPLT OFF. WE CLBED ALMOST TO 12000' BEFORE A CORRECTION WAS INITIATED. THERE WAS A VERY SLIGHT DELAY IN RECOVERY AS THE COPLT MOMENTARILY LOOKED AT THE ABOVE FIELD LEVEL (AFL) ALTIMETER. A SMOOTH RECOVERY TO 11000' WAS MADE. I DO NOT THINK THE DEVIATION COULD HAVE BEEN AVOIDED, BUT THE RECOVERY COULD HAVE BEGUN SOONER. THE CONFUSION CAUSED THE COPLT TO LOOK AT THE WRONG ALTIMETER--ACR USES QFE AND QNH. THE COPLT FLIES JETS IN THE MIL RESERVES, AND WHEN FLUSTERED, REVERTED TO HIS MIL TRNING BY LOOKING AT THE ALTIMETER ON HIS INSTRUMENT PANEL. I HAVE FLOWN WITH THE QFE, QNH SYS FOR 11 YRS AND AMUSED TO IT, BUT I THINK IT HAS OUTLIVED ITS USEFULNESS NOW THAT THERE ARE RADAR ALTIMETERS TO GIVE AGL INFO.

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.