Miscom and misinterp within the cockpit leads to altitude deviation./

Attributes
ACN	132250
Time
Date	198912
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ccv
State Reference	VA
Altitude	msl bound lower : 12500 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	arrival other enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 6000
ASRS Report	132250
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 171 flight time total : 9926 flight time type : 180
ASRS Report	132254
Events
Anomaly	altitude deviation : overshoot altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

First officer flying aircraft southbound toward ccv. ATC requests crossing 10 north of ccv at 16000'. I confirmed the clearance restrictions, and as we were 30 out at 19000' descending, I commented to first officer, 'should be no sweat.' he made no reply. I returned to my manual and moments later ATC requested level-off at 1300'. By that time, we hit 12500', and so we pulled up to 13000'. It was then that I realized we had descended through our assigned altitude. There was no further comment by ATC. I was speechless that my first officer would have made no effort to notify me that he had understood 6000', not 16000', and 6000' was quite impossible to reach in 20 mi. When I said 'no sweat,' he must have begun sweating, profusely. Contributing factors: altitude alert knob blocks my view of 'tens of thousands' digit; i.e., 6000 looks just like 16000, unless I make the extra effort to see around the knob. First officer flies 9 days in national guard each month, and 16 or 17 here with the airline, and frankly I think he's suffering from burnout. Maybe that's why that extra 1000' descent (with 250 to 250 KTS speed reduction) looked feasible--or maybe it didn't register at all. I know how it feels--I've been there myself. Supplemental information from acn 132254: the captain read back the clearance, but I did not hear the readback due to lack of feedback through cockpit speakers (this is fairly common on medium large transport aircraft. It is also common practice for medium large transport crews to rely on these speakers instead of using headsets). I set 6000' in the altitude reminder (it is located on the copilot's side of lower center instrument panel on our company's medium large transport). In actuality the clearance was 16000'. After reading back the clearance, the captain went back to doing some reading he'd been doing most of the flight. The captain's inattn was an obvious factor. In the future, I will ask an inattentive/complacent captain to back me up! I think our reliance on old, questionable cockpit speakers was also a factor. I will consider using a headset in the future. My hearing is not what it used to be, either.

Original NASA ASRS Text

Title: MISCOM AND MISINTERP WITHIN THE COCKPIT LEADS TO ALT DEVIATION./

Narrative: F/O FLYING ACFT SBND TOWARD CCV. ATC REQUESTS XING 10 N OF CCV AT 16000'. I CONFIRMED THE CLRNC RESTRICTIONS, AND AS WE WERE 30 OUT AT 19000' DSNDING, I COMMENTED TO F/O, 'SHOULD BE NO SWEAT.' HE MADE NO REPLY. I RETURNED TO MY MANUAL AND MOMENTS LATER ATC REQUESTED LEVEL-OFF AT 1300'. BY THAT TIME, WE HIT 12500', AND SO WE PULLED UP TO 13000'. IT WAS THEN THAT I REALIZED WE HAD DSNDED THROUGH OUR ASSIGNED ALT. THERE WAS NO FURTHER COMMENT BY ATC. I WAS SPEECHLESS THAT MY F/O WOULD HAVE MADE NO EFFORT TO NOTIFY ME THAT HE HAD UNDERSTOOD 6000', NOT 16000', AND 6000' WAS QUITE IMPOSSIBLE TO REACH IN 20 MI. WHEN I SAID 'NO SWEAT,' HE MUST HAVE BEGUN SWEATING, PROFUSELY. CONTRIBUTING FACTORS: ALT ALERT KNOB BLOCKS MY VIEW OF 'TENS OF THOUSANDS' DIGIT; I.E., 6000 LOOKS JUST LIKE 16000, UNLESS I MAKE THE EXTRA EFFORT TO SEE AROUND THE KNOB. F/O FLIES 9 DAYS IN NATL GUARD EACH MONTH, AND 16 OR 17 HERE WITH THE AIRLINE, AND FRANKLY I THINK HE'S SUFFERING FROM BURNOUT. MAYBE THAT'S WHY THAT EXTRA 1000' DSCNT (WITH 250 TO 250 KTS SPD REDUCTION) LOOKED FEASIBLE--OR MAYBE IT DIDN'T REGISTER AT ALL. I KNOW HOW IT FEELS--I'VE BEEN THERE MYSELF. SUPPLEMENTAL INFO FROM ACN 132254: THE CAPT READ BACK THE CLRNC, BUT I DID NOT HEAR THE READBACK DUE TO LACK OF FEEDBACK THROUGH COCKPIT SPEAKERS (THIS IS FAIRLY COMMON ON MLG ACFT. IT IS ALSO COMMON PRACTICE FOR MLG CREWS TO RELY ON THESE SPEAKERS INSTEAD OF USING HEADSETS). I SET 6000' IN THE ALT REMINDER (IT IS LOCATED ON THE COPLT'S SIDE OF LOWER CENTER INSTRUMENT PANEL ON OUR COMPANY'S MLG). IN ACTUALITY THE CLRNC WAS 16000'. AFTER READING BACK THE CLRNC, THE CAPT WENT BACK TO DOING SOME READING HE'D BEEN DOING MOST OF THE FLT. THE CAPT'S INATTN WAS AN OBVIOUS FACTOR. IN THE FUTURE, I WILL ASK AN INATTENTIVE/COMPLACENT CAPT TO BACK ME UP! I THINK OUR RELIANCE ON OLD, QUESTIONABLE COCKPIT SPEAKERS WAS ALSO A FACTOR. I WILL CONSIDER USING A HEADSET IN THE FUTURE. MY HEARING IS NOT WHAT IT USED TO BE, EITHER.

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.