Narrative:

As captain of air carrier X (sfo-iah) on oct/xa/98 we were on the cugar arrival to iah. Iah ATC had given us several delay vectors prior to issuing a clearance to cross the hoagie fix at 10000 ft and 250 KTS. This clearance was given late requiring a maximum possible descent rate with speed brakes, etc. Several heading changes were assigned and an instruction to intercept the 116.6 305 degree radial. The controller was concerned and questioned us if we were 'going to make hoagie at 10000 ft.' our reply was in the affirmative. He then requested we report when reaching 250 KTS. We acknowledged. Upon reaching 10000 ft about 42 NM, the controller asked what our altitude was. We replied 10000 ft. The controller came back and said 'you're supposed to be at 11000 ft, climb to 11000 ft.' we then climbed immediately to 11000 ft. The controller had earlier requested that we acknowledge our clearance, which we did with a 'roger' to which we believed to be 'report when reaching 250 KTS.' we did not hear an altitude assignment of 11000 ft in the cockpit. Our belief was we were assigned 'hoagie' fix at 10000 ft and 250 KTS. If the controller gave us an interim or subsequent altitude assignment of 11000 ft, we did not understand it. Possibly cockpit noise plus reading checklists interfered with that transmission. The controller believes we acknowledged his instruction with a 'roger.' if this is the case, it was for the 'report when reaching 250 KTS.' voice communication in a high density environment in today's aviation arena can lead to many misread and misunderstood clrncs. We must all be diligent to be clearly understood and certain of clrncs and to comply. I believe we must try to avoid 'slam dunk' approachs by controllers. I also believe that any specific altitude instruction be read back completely and with complete call signs. Also, multiple instructions should be avoided by controllers -- ie heading, altitude, speed, followed by a frequency change.

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Original NASA ASRS Text

Title: MD80 CREW INBOUND TO IAH VIA STAR GIVEN EXPEDITED CLRNC FOR DSCNT TO 10000 FT. DURING DSCNT, CTLR, IN A COMBINED XMISSION, MAY HAVE CHANGED ALT TO 11000 FT AND A SPD OF 250 KIAS.

Narrative: AS CAPT OF ACR X (SFO-IAH) ON OCT/XA/98 WE WERE ON THE CUGAR ARR TO IAH. IAH ATC HAD GIVEN US SEVERAL DELAY VECTORS PRIOR TO ISSUING A CLRNC TO CROSS THE HOAGIE FIX AT 10000 FT AND 250 KTS. THIS CLRNC WAS GIVEN LATE REQUIRING A MAX POSSIBLE DSCNT RATE WITH SPD BRAKES, ETC. SEVERAL HDG CHANGES WERE ASSIGNED AND AN INSTRUCTION TO INTERCEPT THE 116.6 305 DEG RADIAL. THE CTLR WAS CONCERNED AND QUESTIONED US IF WE WERE 'GOING TO MAKE HOAGIE AT 10000 FT.' OUR REPLY WAS IN THE AFFIRMATIVE. HE THEN REQUESTED WE RPT WHEN REACHING 250 KTS. WE ACKNOWLEDGED. UPON REACHING 10000 FT ABOUT 42 NM, THE CTLR ASKED WHAT OUR ALT WAS. WE REPLIED 10000 FT. THE CTLR CAME BACK AND SAID 'YOU'RE SUPPOSED TO BE AT 11000 FT, CLB TO 11000 FT.' WE THEN CLBED IMMEDIATELY TO 11000 FT. THE CTLR HAD EARLIER REQUESTED THAT WE ACKNOWLEDGE OUR CLRNC, WHICH WE DID WITH A 'ROGER' TO WHICH WE BELIEVED TO BE 'RPT WHEN REACHING 250 KTS.' WE DID NOT HEAR AN ALT ASSIGNMENT OF 11000 FT IN THE COCKPIT. OUR BELIEF WAS WE WERE ASSIGNED 'HOAGIE' FIX AT 10000 FT AND 250 KTS. IF THE CTLR GAVE US AN INTERIM OR SUBSEQUENT ALT ASSIGNMENT OF 11000 FT, WE DID NOT UNDERSTAND IT. POSSIBLY COCKPIT NOISE PLUS READING CHKLISTS INTERFERED WITH THAT XMISSION. THE CTLR BELIEVES WE ACKNOWLEDGED HIS INSTRUCTION WITH A 'ROGER.' IF THIS IS THE CASE, IT WAS FOR THE 'RPT WHEN REACHING 250 KTS.' VOICE COM IN A HIGH DENSITY ENVIRONMENT IN TODAY'S AVIATION ARENA CAN LEAD TO MANY MISREAD AND MISUNDERSTOOD CLRNCS. WE MUST ALL BE DILIGENT TO BE CLRLY UNDERSTOOD AND CERTAIN OF CLRNCS AND TO COMPLY. I BELIEVE WE MUST TRY TO AVOID 'SLAM DUNK' APCHS BY CTLRS. I ALSO BELIEVE THAT ANY SPECIFIC ALT INSTRUCTION BE READ BACK COMPLETELY AND WITH COMPLETE CALL SIGNS. ALSO, MULTIPLE INSTRUCTIONS SHOULD BE AVOIDED BY CTLRS -- IE HDG, ALT, SPD, FOLLOWED BY A FREQ CHANGE.

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.