An air carrier medium large transport climbed in response to a TCASII command.

Attributes
ACN	252163
Time
Date	199309
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pmm
State Reference	MI
Altitude	msl bound lower : 23000 msl bound upper : 23700
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 90 flight time total : 8000 flight time type : 3000
ASRS Report	252163
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 500 vertical : 700
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were on the pmm arrival for landing at ord. We were level at FL230. Sky conditions were hazy, some clouds, choppy air, and were looking directly into the setting sun. Without any warning, TCASII screen displayed a red target, and simultaneously we received an aural warning to climb. Immediately another aural warning said, 'increase rate of climb' so I did. We tried to call ZAU and advise them what we were doing but he was very busy as usual. The moment TCASII said, 'clear of traffic,' we started back down to maintain FL230. We had gotten to 23.7. Once we got ahold of ZAU they said a 'light twin' was level at 220. Shortly after TCASII said, 'clear of traffic,' we saw a smaller type aircraft off of our right front heading nne. Aircraft was below us. Now, with all the haze, clouds, blinding sunset, I cannot honestly judge the distance. ATC said we conflicted with no one.

Original NASA ASRS Text

Title: AN ACR MLG CLBED IN RESPONSE TO A TCASII COMMAND.

Narrative: WE WERE ON THE PMM ARR FOR LNDG AT ORD. WE WERE LEVEL AT FL230. SKY CONDITIONS WERE HAZY, SOME CLOUDS, CHOPPY AIR, AND WERE LOOKING DIRECTLY INTO THE SETTING SUN. WITHOUT ANY WARNING, TCASII SCREEN DISPLAYED A RED TARGET, AND SIMULTANEOUSLY WE RECEIVED AN AURAL WARNING TO CLB. IMMEDIATELY ANOTHER AURAL WARNING SAID, 'INCREASE RATE OF CLB' SO I DID. WE TRIED TO CALL ZAU AND ADVISE THEM WHAT WE WERE DOING BUT HE WAS VERY BUSY AS USUAL. THE MOMENT TCASII SAID, 'CLR OF TFC,' WE STARTED BACK DOWN TO MAINTAIN FL230. WE HAD GOTTEN TO 23.7. ONCE WE GOT AHOLD OF ZAU THEY SAID A 'LIGHT TWIN' WAS LEVEL AT 220. SHORTLY AFTER TCASII SAID, 'CLR OF TFC,' WE SAW A SMALLER TYPE ACFT OFF OF OUR R FRONT HDG NNE. ACFT WAS BELOW US. NOW, WITH ALL THE HAZE, CLOUDS, BLINDING SUNSET, I CANNOT HONESTLY JUDGE THE DISTANCE. ATC SAID WE CONFLICTED WITH NO ONE.

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.