Air carrier on descent cleared to 8000 ft. On readback told 4000 ft. Passing 6000 ft told clearance ...

Attributes
ACN	200741
Time
Date	199201
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 6000 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : cfi pilot : atp pilot : commercial
Experience	flight time last 90 days : 90 flight time total : 3500 flight time type : 130
ASRS Report	200741
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : published procedure other anomaly other
Independent Detector	other controllera other flight crewa other other : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

We were cleared to 10000 contact ord approach inbound for vectors landing runway 4R, I was flying and my first officer talking. Approach cleared us to 8000 ft, my first officer read back and approach emphatically replied 4000 ft! Which my first officer dutifully read back and set in the altitude select window. He then asked for a repeat and was told 4000 ft again. I guess between 6500 and 6000 approach asked what altitude we were passing and 'what are you doing there, you're supposed to be 8000 ft?' by the time all was confirmed we bottomed out at 5500 before climbing back to 8000 ft. It was a little unnerving -- since there was a heavy load of inbound traffic and a lot of chatter. We elected not to argue the point -- a followup call to the TRACON supervisor was made. He said there was 'no problem' (with an altitude violation) and the controller got a little 'mixed up' and there had been 'no conflicting traffic.' thank god! The thought turns my stomach! We were all lucky this time. TRACON at ord regularly issues 5-6 instructions at once in a single burst -- with no time for anyone to break in between. I do not envy those controllers their jobs. Wouldn't you say that at times the volume at ord exceeds ATC capability for safe operations? I often wonder about it.

Original NASA ASRS Text

Title: ACR ON DSCNT CLRED TO 8000 FT. ON READBACK TOLD 4000 FT. PASSING 6000 FT TOLD CLRNC WAS TO 8000 FT.

Narrative: WE WERE CLRED TO 10000 CONTACT ORD APCH INBOUND FOR VECTORS LNDG RWY 4R, I WAS FLYING AND MY FO TALKING. APCH CLRED US TO 8000 FT, MY FO READ BACK AND APCH EMPHATICALLY REPLIED 4000 FT! WHICH MY FO DUTIFULLY READ BACK AND SET IN THE ALT SELECT WINDOW. HE THEN ASKED FOR A REPEAT AND WAS TOLD 4000 FT AGAIN. I GUESS BTWN 6500 AND 6000 APCH ASKED WHAT ALT WE WERE PASSING AND 'WHAT ARE YOU DOING THERE, YOU'RE SUPPOSED TO BE 8000 FT?' BY THE TIME ALL WAS CONFIRMED WE BOTTOMED OUT AT 5500 BEFORE CLBING BACK TO 8000 FT. IT WAS A LITTLE UNNERVING -- SINCE THERE WAS A HVY LOAD OF INBOUND TFC AND A LOT OF CHATTER. WE ELECTED NOT TO ARGUE THE POINT -- A FOLLOWUP CALL TO THE TRACON SUPVR WAS MADE. HE SAID THERE WAS 'NO PROBLEM' (WITH AN ALT VIOLATION) AND THE CTLR GOT A LITTLE 'MIXED UP' AND THERE HAD BEEN 'NO CONFLICTING TFC.' THANK GOD! THE THOUGHT TURNS MY STOMACH! WE WERE ALL LUCKY THIS TIME. TRACON AT ORD REGULARLY ISSUES 5-6 INSTRUCTIONS AT ONCE IN A SINGLE BURST -- WITH NO TIME FOR ANYONE TO BREAK IN BTWN. I DO NOT ENVY THOSE CTLRS THEIR JOBS. WOULDN'T YOU SAY THAT AT TIMES THE VOLUME AT ORD EXCEEDS ATC CAPABILITY FOR SAFE OPS? I OFTEN WONDER ABOUT IT.

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.

Air carrier on descent cleared to 8000 ft. On readback told 4000 ft. Passing 6000 ft told clearance was to 8000 ft.