DC9 experienced TCASII RA during descent into ord near FL250 with another air carrier due to an alti...

Attributes
ACN	599353
Time
Date	200311
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : mkg.vortac
State Reference	MI
Altitude	msl bound lower : 24000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 50
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 450 flight time total : 16000 flight time type : 7000
ASRS Report	599353
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : overshoot conflict : airborne critical non adherence : clearance other spatial deviation
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	controller : issued new clearance controller : issued advisory flight crew : took evasive action
Miss Distance	horizontal : 1000 vertical : 600
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While cruising at FL290, we were instructed to descend to FL240 by ZAU. We acknowledged and began a descent to FL240. Passing FL280, center asked us to expedite to FL240. We acknowledged and increased descent rate. We heard an air carrier Y jet being given descent instructions also. ZAU asked us to be below FL250 in 1 min or less (we were at FL265). We acknowledged and increased descent rate to 2000-2500 FPM. ZAU asked air carrier Y flight his altitude. He said 'FL240.' ZAU said he was only cleared to FL260. Air carrier Y said 'he put the wrong thing in the window.' ZAU told air carrier Y to descend immediately to FL230. At this time we had a visual on air carrier Y flight at our 11-12 O'clock position. I had stopped descending at FL245 and began maneuvering to avoid air carrier Y. TCASII gave us an RA to 'descend.' because of visual with air carrier Y below us, we climbed and turned at 10-15 degrees left. Center then asked us if we were at FL250. We said 'no, we never heard instructions to climb to FL250 but, we could climb there.' they, (ZAU) said, 'no, descend to be at FL230 at geiber intersection.' our TCASII gave us 'clear of conflict.'

Original NASA ASRS Text

Title: DC9 EXPERIENCED TCASII RA DURING DSCNT INTO ORD NEAR FL250 WITH ANOTHER ACR DUE TO AN ALT OVERSHOOT.

Narrative: WHILE CRUISING AT FL290, WE WERE INSTRUCTED TO DSND TO FL240 BY ZAU. WE ACKNOWLEDGED AND BEGAN A DSCNT TO FL240. PASSING FL280, CTR ASKED US TO EXPEDITE TO FL240. WE ACKNOWLEDGED AND INCREASED DSCNT RATE. WE HEARD AN ACR Y JET BEING GIVEN DSCNT INSTRUCTIONS ALSO. ZAU ASKED US TO BE BELOW FL250 IN 1 MIN OR LESS (WE WERE AT FL265). WE ACKNOWLEDGED AND INCREASED DSCNT RATE TO 2000-2500 FPM. ZAU ASKED ACR Y FLT HIS ALT. HE SAID 'FL240.' ZAU SAID HE WAS ONLY CLRED TO FL260. ACR Y SAID 'HE PUT THE WRONG THING IN THE WINDOW.' ZAU TOLD ACR Y TO DSND IMMEDIATELY TO FL230. AT THIS TIME WE HAD A VISUAL ON ACR Y FLT AT OUR 11-12 O'CLOCK POS. I HAD STOPPED DSNDING AT FL245 AND BEGAN MANEUVERING TO AVOID ACR Y. TCASII GAVE US AN RA TO 'DSND.' BECAUSE OF VISUAL WITH ACR Y BELOW US, WE CLBED AND TURNED AT 10-15 DEGS L. CTR THEN ASKED US IF WE WERE AT FL250. WE SAID 'NO, WE NEVER HEARD INSTRUCTIONS TO CLB TO FL250 BUT, WE COULD CLB THERE.' THEY, (ZAU) SAID, 'NO, DSND TO BE AT FL230 AT GEIBER INTXN.' OUR TCASII GAVE US 'CLR OF CONFLICT.'

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.

DC9 experienced TCASII RA during descent into ord near FL250 with another air carrier due to an altitude overshoot.