B757-200 crew had multiple altitude overshoots when following the flight guidance system.

Attributes
ACN	583229
Time
Date	200305
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : n90.tracon
State Reference	NY
Altitude	msl bound lower : 4000 msl bound upper : 4299
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90.tracon
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	departure : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 60 flight time total : 12800 flight time type : 600
ASRS Report	583229
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : published procedure non adherence : company policies non adherence : clearance non adherence : far
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

A visual takeoff at very low gross weight, this B757-200 wants to overshoot altitude with just the flight director coupled. I think the air data computer just can't handle the following conditions: low gross weight, low initial (3000 ft and 4000 ft) altitude and high rate of climb/closure rates. Upon departure at swf the aircraft mode annunciator 'captured' for 3000 ft, but upon selecting 4000 ft and flight level change, it overshot by 299 ft. This was flight director hand flown. The next morning in a 26 hour supplemental duty day part 121, if you can believe that, upon departure from abe back to swf with the autoplt coupled (to prevent it again) the aircraft overshot 5000 ft by 299 ft. It captured either 3000 ft or 4000 ft initially, but ATC gave us 5000 ft and the autoplt/flight director overshot again. The first event was in the vicinity of huo VOR, the 2ND near fjc. Later in the week, the aircraft captured 3000 ft nicely, but upon selecting 5000 ft and VNAV, it captured 3400 ft. Very spooky! Do B757's have air data computer updates that refine their calculation abilities?

Original NASA ASRS Text

Title: B757-200 CREW HAD MULTIPLE ALT OVERSHOOTS WHEN FOLLOWING THE FLT GUIDANCE SYS.

Narrative: A VISUAL TKOF AT VERY LOW GROSS WT, THIS B757-200 WANTS TO OVERSHOOT ALT WITH JUST THE FLT DIRECTOR COUPLED. I THINK THE AIR DATA COMPUTER JUST CAN'T HANDLE THE FOLLOWING CONDITIONS: LOW GROSS WT, LOW INITIAL (3000 FT AND 4000 FT) ALT AND HIGH RATE OF CLB/CLOSURE RATES. UPON DEP AT SWF THE ACFT MODE ANNUNCIATOR 'CAPTURED' FOR 3000 FT, BUT UPON SELECTING 4000 FT AND FLT LEVEL CHANGE, IT OVERSHOT BY 299 FT. THIS WAS FLT DIRECTOR HAND FLOWN. THE NEXT MORNING IN A 26 HR SUPPLEMENTAL DUTY DAY PART 121, IF YOU CAN BELIEVE THAT, UPON DEP FROM ABE BACK TO SWF WITH THE AUTOPLT COUPLED (TO PREVENT IT AGAIN) THE ACFT OVERSHOT 5000 FT BY 299 FT. IT CAPTURED EITHER 3000 FT OR 4000 FT INITIALLY, BUT ATC GAVE US 5000 FT AND THE AUTOPLT/FLT DIRECTOR OVERSHOT AGAIN. THE FIRST EVENT WAS IN THE VICINITY OF HUO VOR, THE 2ND NEAR FJC. LATER IN THE WEEK, THE ACFT CAPTURED 3000 FT NICELY, BUT UPON SELECTING 5000 FT AND VNAV, IT CAPTURED 3400 FT. VERY SPOOKY! DO B757'S HAVE AIR DATA COMPUTER UPDATES THAT REFINE THEIR CALCULATION ABILITIES?

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.