A B757-200 crew, in descent to stl, overshot an ATC imposed altitude restr.

Attributes
ACN	557816
Time
Date	200208
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : vhp.vortac
State Reference	IN
Altitude	msl bound lower : 27500 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : vandalia
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7000 flight time type : 920
ASRS Report	557816
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment : tcas other controllera
Resolutory Action	flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew other
Miss Distance	horizontal : 20000 vertical : 500
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

ATC took us 15 degrees right off the vandelia STAR into stl. Next transmission told us to descend to FL270. The captain, who was working the radio, read back FL270. I was the PF. I am not sure that the controller said FL270, however, I am sure the captain read back FL270. We had 2 jump seaters in the cockpit. If I recall correctly, they told us to expedite the descent through FL310. I did expedite the descent. At approximately FL278, we got a TA on the TCASII. The altitude of the other aircraft appeared to be at FL270 on the TCASII. We never got a visual sighting. I arrested the descent and queried the captain. We were about FL275 when around the same time ATC asked if we were at FL280. I disconnected the autoplt and pushed up the throttles. We were at FL280 within 10 seconds. There was no RA on the TCASII. I do not know if the controller said FL280 or FL270. Conversation about our future was running high. These distrs led me to not hear everything ATC said. I did hear the captain. The captain was a very good pilot, and I trusted what he said. There is where I see the problem. Although nothing happened because of our equipment and ATC quickly coming back to us, I believe this may not have occurred if there was no conversion when we started on the STAR, that assumes that ATC had told us FL280 and not FL270.

Original NASA ASRS Text

Title: A B757-200 CREW, IN DSCNT TO STL, OVERSHOT AN ATC IMPOSED ALT RESTR.

Narrative: ATC TOOK US 15 DEGS R OFF THE VANDELIA STAR INTO STL. NEXT XMISSION TOLD US TO DSND TO FL270. THE CAPT, WHO WAS WORKING THE RADIO, READ BACK FL270. I WAS THE PF. I AM NOT SURE THAT THE CTLR SAID FL270, HOWEVER, I AM SURE THE CAPT READ BACK FL270. WE HAD 2 JUMP SEATERS IN THE COCKPIT. IF I RECALL CORRECTLY, THEY TOLD US TO EXPEDITE THE DSCNT THROUGH FL310. I DID EXPEDITE THE DSCNT. AT APPROX FL278, WE GOT A TA ON THE TCASII. THE ALT OF THE OTHER ACFT APPEARED TO BE AT FL270 ON THE TCASII. WE NEVER GOT A VISUAL SIGHTING. I ARRESTED THE DSCNT AND QUERIED THE CAPT. WE WERE ABOUT FL275 WHEN AROUND THE SAME TIME ATC ASKED IF WE WERE AT FL280. I DISCONNECTED THE AUTOPLT AND PUSHED UP THE THROTTLES. WE WERE AT FL280 WITHIN 10 SECONDS. THERE WAS NO RA ON THE TCASII. I DO NOT KNOW IF THE CTLR SAID FL280 OR FL270. CONVERSATION ABOUT OUR FUTURE WAS RUNNING HIGH. THESE DISTRS LED ME TO NOT HEAR EVERYTHING ATC SAID. I DID HEAR THE CAPT. THE CAPT WAS A VERY GOOD PLT, AND I TRUSTED WHAT HE SAID. THERE IS WHERE I SEE THE PROB. ALTHOUGH NOTHING HAPPENED BECAUSE OF OUR EQUIP AND ATC QUICKLY COMING BACK TO US, I BELIEVE THIS MAY NOT HAVE OCCURRED IF THERE WAS NO CONVERSION WHEN WE STARTED ON THE STAR, THAT ASSUMES THAT ATC HAD TOLD US FL280 AND NOT FL270.

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.