Unauthorized altitude change because of a TCASII RA.

Attributes
ACN	242522
Time
Date	199305
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : obk airport : ord
State Reference	IL
Altitude	msl bound lower : 9400 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 180 flight time total : 14500 flight time type : 220
ASRS Report	242522
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence other other anomaly
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Arriving ord on pullman 2 arrival 10000 ft, 300 KTS assigned. TA approximately 6 mi 12 O'clock and 300 to 400 ft. RA at 5 NM 12. Descend RA. Captain pushed over turned left. Clear of TA at approximately 9400 ft MSL. I notified approach at about 9800 ft in descent. Approach stated it was VFR traffic and he forgot to advise and to continue descent to 8000 ft. As a result we reached 8000 ft at 300 KTS and then slowed to newly assigned 210 KTS. Shortly thereafter, we somehow (I think I accidentally hit a transfer switch) got on tower frequency and were out of touch with approach for about 15 NM. We noted this error, got back on approach frequency and landed without further problems. Our habit pattern was changed i.e., slow at 10000 prior to descent, by the RA so the excess speed was maintained to 8000 ft instead of slowing after the conflict was resolved. I let myself become distracted by what I felt was poor performance on my part by not advising the captain to slow after the conflict resolution and somehow got us on the wrong frequency. Moral -- don't dwell on a screw-up (perceived or otherwise) or you'll probably screw up again.

Original NASA ASRS Text

Title: UNAUTH ALT CHANGE BECAUSE OF A TCASII RA.

Narrative: ARRIVING ORD ON PULLMAN 2 ARR 10000 FT, 300 KTS ASSIGNED. TA APPROX 6 MI 12 O'CLOCK AND 300 TO 400 FT. RA AT 5 NM 12. DSND RA. CAPT PUSHED OVER TURNED L. CLR OF TA AT APPROX 9400 FT MSL. I NOTIFIED APCH AT ABOUT 9800 FT IN DSCNT. APCH STATED IT WAS VFR TFC AND HE FORGOT TO ADVISE AND TO CONTINUE DSCNT TO 8000 FT. AS A RESULT WE REACHED 8000 FT AT 300 KTS AND THEN SLOWED TO NEWLY ASSIGNED 210 KTS. SHORTLY THEREAFTER, WE SOMEHOW (I THINK I ACCIDENTALLY HIT A TRANSFER SWITCH) GOT ON TWR FREQ AND WERE OUT OF TOUCH WITH APCH FOR ABOUT 15 NM. WE NOTED THIS ERROR, GOT BACK ON APCH FREQ AND LANDED WITHOUT FURTHER PROBS. OUR HABIT PATTERN WAS CHANGED I.E., SLOW AT 10000 PRIOR TO DSCNT, BY THE RA SO THE EXCESS SPD WAS MAINTAINED TO 8000 FT INSTEAD OF SLOWING AFTER THE CONFLICT WAS RESOLVED. I LET MYSELF BECOME DISTRACTED BY WHAT I FELT WAS POOR PERFORMANCE ON MY PART BY NOT ADVISING THE CAPT TO SLOW AFTER THE CONFLICT RESOLUTION AND SOMEHOW GOT US ON THE WRONG FREQ. MORAL -- DON'T DWELL ON A SCREW-UP (PERCEIVED OR OTHERWISE) OR YOU'LL PROBABLY SCREW UP AGAIN.

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.