Narrative:

On left base, about 15 mi out, approach cleared us for the ILS 36 approach to dca. We were descending at the time and she spoke very rapidly, adding something like 'cross oxonn at 1600, pisca at 2500'. The captain set 1600 in the altitude alert and I, also hearing/remembering 1600, descended through 2000 when the second officer said we're only cleared to 2500 till past pisca (10.2 DME). I began a climb and the captain told approach we had misunderstood the altitude restriction, were climbing back to 2500, and apologized. The controller said our altitude was ok, since there wouldn't be any VFR traffic below the TCA where we were in that kind of WX (about 600 overcast 1 1/2 runway), and that's the reason for the approach clearance with the 2500 restriction. I hadn't flown in over 4 months (medical leave) and was getting a line check, so I wasn't as sharp as I hope I usually am. The controller spoke way too fast and, as usually is the case, gave too many directions in one clearance, ie, a turn, cleared to intercept the localizer, approach clearance to a specific runway, 2 altitudes, and a specific airspeed. More than about 3 numbers in one clearance seems a bit too much. Luckily, no one got hurt, but the potential was there. Also shows the value of a 3-MAN crew. I honestly believe that safety would be enhanced if controllers would slow their approach clrncs, and limit each transmission to no more than 3 instructions.

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Original NASA ASRS Text

Title: ACR LGT ALT DEVIATION OVERSHOT DURING DESCENT INTO DCA.

Narrative: ON LEFT BASE, ABOUT 15 MI OUT, APCH CLRED US FOR THE ILS 36 APCH TO DCA. WE WERE DESCENDING AT THE TIME AND SHE SPOKE VERY RAPIDLY, ADDING SOMETHING LIKE 'CROSS OXONN AT 1600, PISCA AT 2500'. THE CAPT SET 1600 IN THE ALT ALERT AND I, ALSO HEARING/REMEMBERING 1600, DESCENDED THROUGH 2000 WHEN THE S/O SAID WE'RE ONLY CLRED TO 2500 TILL PAST PISCA (10.2 DME). I BEGAN A CLIMB AND THE CAPT TOLD APCH WE HAD MISUNDERSTOOD THE ALT RESTRICTION, WERE CLIMBING BACK TO 2500, AND APOLOGIZED. THE CTLR SAID OUR ALT WAS OK, SINCE THERE WOULDN'T BE ANY VFR TFC BELOW THE TCA WHERE WE WERE IN THAT KIND OF WX (ABOUT 600 OVCST 1 1/2 RWY), AND THAT'S THE REASON FOR THE APCH CLRNC WITH THE 2500 RESTRICTION. I HADN'T FLOWN IN OVER 4 MONTHS (MEDICAL LEAVE) AND WAS GETTING A LINE CHECK, SO I WASN'T AS SHARP AS I HOPE I USUALLY AM. THE CTLR SPOKE WAY TOO FAST AND, AS USUALLY IS THE CASE, GAVE TOO MANY DIRECTIONS IN ONE CLRNC, IE, A TURN, CLRED TO INTERCEPT THE LOC, APCH CLRNC TO A SPECIFIC RWY, 2 ALTS, AND A SPECIFIC AIRSPEED. MORE THAN ABOUT 3 NUMBERS IN ONE CLRNC SEEMS A BIT TOO MUCH. LUCKILY, NO ONE GOT HURT, BUT THE POTENTIAL WAS THERE. ALSO SHOWS THE VALUE OF A 3-MAN CREW. I HONESTLY BELIEVE THAT SAFETY WOULD BE ENHANCED IF CTLRS WOULD SLOW THEIR APCH CLRNCS, AND LIMIT EACH XMISSION TO NO MORE THAN 3 INSTRUCTIONS.

Data retrieved from NASA's ASRS site as of August 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.