Possible overweight takeoff. Unable callback.

Attributes
ACN	138956
Time
Date	199003
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord
State Reference	IL
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : takeoff
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 210 flight time total : 7000 flight time type : 1300
ASRS Report	138956
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 210 flight time total : 3000 flight time type : 210
ASRS Report	139204
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

#2 engine mixed air/cowl anti-ice valve was wired open takeoff weight penalty per airport analysis was 8100 pounds. Our runway limited weight was about 188000 pounds and our gross weight was 174000 pounds. Departed chicago 27L with headwinds. Normal takeoff/.climb with no performance problems. Upon closer scrutiny after the flight it appears we may have been too heavy because the airport analysis seems to require that this 8100 pounds be deducted also from the aircraft limit weight (178000) and then the lower of these weights used. This surprises me because the weight reduction for anti-ice use is 2100 pounds. Nevertheless, if this is the correct interpretation, as it seems to be on closer examination the runway limit with penalty was 179900 and our aircraft limit with penalty was 169900. With our takeoff weight of 174400 pounds we exceeded the lower of these weights by 4500 pounds. As I said earlier, since the weight adjustment for anti-ice on is 2100 pounds and the aircraft limit weight is a structural limit, if we violated our legal takeoff weight it seems to me to be a matter of semantics. Most certainly there was no attempt to violate procedure. It is easier to find these 'loopholes' after the flight than in line for takeoff at O'hare.

Original NASA ASRS Text

Title: POSSIBLE OVERWEIGHT TKOF. UNABLE CALLBACK.

Narrative: #2 ENG MIXED AIR/COWL ANTI-ICE VALVE WAS WIRED OPEN TKOF WT PENALTY PER ARPT ANALYSIS WAS 8100 LBS. OUR RWY LIMITED WT WAS ABOUT 188000 LBS AND OUR GROSS WT WAS 174000 LBS. DEPARTED CHICAGO 27L WITH HEADWINDS. NORMAL TKOF/.CLB WITH NO PERFORMANCE PROBS. UPON CLOSER SCRUTINY AFTER THE FLT IT APPEARS WE MAY HAVE BEEN TOO HEAVY BECAUSE THE ARPT ANALYSIS SEEMS TO REQUIRE THAT THIS 8100 LBS BE DEDUCTED ALSO FROM THE ACFT LIMIT WT (178000) AND THEN THE LOWER OF THESE WTS USED. THIS SURPRISES ME BECAUSE THE WT REDUCTION FOR ANTI-ICE USE IS 2100 LBS. NEVERTHELESS, IF THIS IS THE CORRECT INTERPRETATION, AS IT SEEMS TO BE ON CLOSER EXAMINATION THE RWY LIMIT WITH PENALTY WAS 179900 AND OUR ACFT LIMIT WITH PENALTY WAS 169900. WITH OUR TKOF WT OF 174400 LBS WE EXCEEDED THE LOWER OF THESE WTS BY 4500 LBS. AS I SAID EARLIER, SINCE THE WT ADJUSTMENT FOR ANTI-ICE ON IS 2100 LBS AND THE ACFT LIMIT WT IS A STRUCTURAL LIMIT, IF WE VIOLATED OUR LEGAL TKOF WT IT SEEMS TO ME TO BE A MATTER OF SEMANTICS. MOST CERTAINLY THERE WAS NO ATTEMPT TO VIOLATE PROC. IT IS EASIER TO FIND THESE 'LOOPHOLES' AFTER THE FLT THAN IN LINE FOR TKOF AT O'HARE.

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.