Flight crew of B737-300 aircraft, PNF first officer off radio talking to their company while PF capt...

Attributes
ACN	387050
Time
Date	199711
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ipl
State Reference	CA
Altitude	msl bound lower : 11400 msl bound upper : 12000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute airway : zla
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 6000
ASRS Report	387050
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 250 flight time total : 10000 flight time type : 6000
ASRS Report	387521
Events
Anomaly	altitude deviation : overshoot 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	other

Narrative:

While en route to san in the vicinity of the bard VORTAC, we encountered in-flight moderate rime icing and felt obligated to report same to our company dispatch. I then told the captain (PF) that I would be off the ATC radio contacting dispatch. I was off ATC radio for several mins attempting contact with our dispatch. During that time I observed the captain putting 10000 ft in the altitude select window of the MCP (mode control panel) which coincided with our filed STAR (BARET4) crossing restr for the pillo intersection on the arrival. The captain began descent while I was off the air. As soon as I returned he pointed to the MCP and stated '10000 ft' and I then went off ATC radio to obtain the san ATIS and again to obtain our gate assignment from san operations. By the time I returned to the ATC radio we were descending through 11400 ft rapidly and I heard the controller stating something like 'abc, say altitude' and the captain replying our altitude and descending to 10000 ft. The controller said '12000 ft' was the assignment but to maintain '11000 ft now, traffic at ...' this was all rather sudden and confusing to me as I had not heard the original clearance but could tell the controller was worried from the tone of his voice. The captain made no attempt to change our rate of descent and we observed an aircraft some distance to our right passing eastbound just below us but at what seemed like several mi north of our course. I asked the captain what had happened and he offered no explanation other than that he had the traffic in sight all along. When I asked what our clearance was he said '10000 ft' and I asked if there was any problem in the descent, he did not reply. Nothing was said by the controller other than to hand us off to the approach controller (socal approach) and our approach and subsequent landing were normal. I cannot offer a solution to a problem such as this, since I believe that this is a recurring problem in a 2-PERSON cockpit -- simply task overload. When one person is performing non-flying duties, the aircraft becomes a single crewed one.

Original NASA ASRS Text

Title: FLC OF B737-300 ACFT, PNF FO OFF RADIO TALKING TO THEIR COMPANY WHILE PF CAPT RECEIVES AND READS BACK DSCNT CLRNC. CTLR INTERVENES WHEN SEEING ACFT DSNDING THROUGH 12000 FT. RPTR CAPT TELLS CTLR HE READ BACK 10000 FT. NO CONFLICT.

Narrative: WHILE ENRTE TO SAN IN THE VICINITY OF THE BARD VORTAC, WE ENCOUNTERED INFLT MODERATE RIME ICING AND FELT OBLIGATED TO RPT SAME TO OUR COMPANY DISPATCH. I THEN TOLD THE CAPT (PF) THAT I WOULD BE OFF THE ATC RADIO CONTACTING DISPATCH. I WAS OFF ATC RADIO FOR SEVERAL MINS ATTEMPTING CONTACT WITH OUR DISPATCH. DURING THAT TIME I OBSERVED THE CAPT PUTTING 10000 FT IN THE ALT SELECT WINDOW OF THE MCP (MODE CTL PANEL) WHICH COINCIDED WITH OUR FILED STAR (BARET4) XING RESTR FOR THE PILLO INTXN ON THE ARR. THE CAPT BEGAN DSCNT WHILE I WAS OFF THE AIR. AS SOON AS I RETURNED HE POINTED TO THE MCP AND STATED '10000 FT' AND I THEN WENT OFF ATC RADIO TO OBTAIN THE SAN ATIS AND AGAIN TO OBTAIN OUR GATE ASSIGNMENT FROM SAN OPS. BY THE TIME I RETURNED TO THE ATC RADIO WE WERE DSNDING THROUGH 11400 FT RAPIDLY AND I HEARD THE CTLR STATING SOMETHING LIKE 'ABC, SAY ALT' AND THE CAPT REPLYING OUR ALT AND DSNDING TO 10000 FT. THE CTLR SAID '12000 FT' WAS THE ASSIGNMENT BUT TO MAINTAIN '11000 FT NOW, TFC AT ...' THIS WAS ALL RATHER SUDDEN AND CONFUSING TO ME AS I HAD NOT HEARD THE ORIGINAL CLRNC BUT COULD TELL THE CTLR WAS WORRIED FROM THE TONE OF HIS VOICE. THE CAPT MADE NO ATTEMPT TO CHANGE OUR RATE OF DSCNT AND WE OBSERVED AN ACFT SOME DISTANCE TO OUR R PASSING EBOUND JUST BELOW US BUT AT WHAT SEEMED LIKE SEVERAL MI N OF OUR COURSE. I ASKED THE CAPT WHAT HAD HAPPENED AND HE OFFERED NO EXPLANATION OTHER THAN THAT HE HAD THE TFC IN SIGHT ALL ALONG. WHEN I ASKED WHAT OUR CLRNC WAS HE SAID '10000 FT' AND I ASKED IF THERE WAS ANY PROB IN THE DSCNT, HE DID NOT REPLY. NOTHING WAS SAID BY THE CTLR OTHER THAN TO HAND US OFF TO THE APCH CTLR (SOCAL APCH) AND OUR APCH AND SUBSEQUENT LNDG WERE NORMAL. I CANNOT OFFER A SOLUTION TO A PROB SUCH AS THIS, SINCE I BELIEVE THAT THIS IS A RECURRING PROB IN A 2-PERSON COCKPIT -- SIMPLY TASK OVERLOAD. WHEN ONE PERSON IS PERFORMING NON-FLYING DUTIES, THE ACFT BECOMES A SINGLE CREWED ONE.

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.

Flight crew of B737-300 aircraft, PNF first officer off radio talking to their company while PF captain receives and reads back descent clearance. Controller intervenes when seeing aircraft descending through 12000 ft. Reporter captain tells controller he read back 10000 ft. No conflict.