TCASII causes undershoot of altitude crossing restr 45 southwest ord.

Attributes
ACN	344300
Time
Date	199608
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ord
State Reference	IL
Altitude	msl bound lower : 11000 msl bound upper : 11500
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau tracon : elm
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	344300
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : crossing restriction not met conflict : airborne less severe non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Received clearance to cross 45 southwest of ord VOR at 11000 ft. At approximately 12000 ft and 50 DME ZAU controller issued a TA, at 1 O'clock 5 mi 10500 ft unverified. I began to shallow my descent rate to less than 500 FPM. TCASII showed no traffic until about 11200 ft at 43 DME. We received a TA immediately followed by a RA to climb. TCASII vsi indicated 2000 FPM climb as a resolution. Disengaged autoplt and climbed back to 11500 ft when TCASII issued clear of traffic. Never saw target. Advised ATC of RA and action taken.

Original NASA ASRS Text

Title: TCASII CAUSES UNDERSHOOT OF ALT XING RESTR 45 SW ORD.

Narrative: RECEIVED CLRNC TO CROSS 45 SW OF ORD VOR AT 11000 FT. AT APPROX 12000 FT AND 50 DME ZAU CTLR ISSUED A TA, AT 1 O'CLOCK 5 MI 10500 FT UNVERIFIED. I BEGAN TO SHALLOW MY DSCNT RATE TO LESS THAN 500 FPM. TCASII SHOWED NO TFC UNTIL ABOUT 11200 FT AT 43 DME. WE RECEIVED A TA IMMEDIATELY FOLLOWED BY A RA TO CLB. TCASII VSI INDICATED 2000 FPM CLB AS A RESOLUTION. DISENGAGED AUTOPLT AND CLBED BACK TO 11500 FT WHEN TCASII ISSUED CLR OF TFC. NEVER SAW TARGET. ADVISED ATC OF RA AND ACTION TAKEN.

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.