B767 on vectors to ogg, expecting visual approach, descended below ATC assigned altitude.

Attributes
ACN	608365
Time
Date	200402
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : ogg.airport
State Reference	HI
Altitude	msl bound lower : 3000 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : hcf.tracon
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 6500 flight time type : 2700
ASRS Report	608365
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 11000 flight time type : 4000
ASRS Report	608364
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather inflight encounter other non adherence : clearance
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment
Supplementary
Problem Areas	Weather Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I ws the PF hand flying the arrival into ogg. The initial clearance was to 7000 ft, then we got further cleared to 5000 ft. Abeam the airport, ATC cleared us to 3500 ft. At the time, we had the airport in sight and the aircraft in front of us in sight (a B767). There was a small cloud buildup directly in front of us. The bottoms of these buildups were around 3200 ft MSL. At this time, ATC asked us if we had the aircraft in front in sight. The captain acknowledged the controller, but did not report aircraft in sight. I was expecting him to call traffic in sight and be cleared for the visual. I have flown into ogg numerous times and have been cleared for the visual every time. At this time, my scan was 95% outside the airplane. I was looking at the airport, the aircraft in front of us and the cloud buildup in front of us that I wanted to avoid. Looking back into the cockpit, I noticed the altimeter reading around 3000 ft. ATC then asked us what our altitude was and told us to maintain 3000 ft. He then asked us if we had the airport in sight and cleared us for the visual when we said yes. The rest of the approach and landing were uneventful. The human factors that led up to this altitude deviation were: 1) high cockpit activity in the approach phase without the autoplt on, 2) wanting and expecting a visual clearance to avoid a buildup and not asking for one or getting one, assuming the controller was going to give it to us. Supplemental information from acn 608364: my first officer said he would expedite his descent to avoid a deck of clouds. These clouds looked like they would give us some pretty good jolts. ATC gave us a heading to fly and pointed out a heavy jet for us to follow on the visual approach. I saw the jet, but because I was not sure if we could keep it in sight and because I wanted more spacing for wake turbulence avoidance, I did not call the jet in sight yet. My first officer thought that I did call the jet in sight and that we were cleared for the visual approach. He descended to 3000 ft to avoid the jolts. This resulted in an altitude deviation.

Original NASA ASRS Text

Title: B767 ON VECTORS TO OGG, EXPECTING VISUAL APCH, DSNDED BELOW ATC ASSIGNED ALT.

Narrative: I WS THE PF HAND FLYING THE ARR INTO OGG. THE INITIAL CLRNC WAS TO 7000 FT, THEN WE GOT FURTHER CLRED TO 5000 FT. ABEAM THE ARPT, ATC CLRED US TO 3500 FT. AT THE TIME, WE HAD THE ARPT IN SIGHT AND THE ACFT IN FRONT OF US IN SIGHT (A B767). THERE WAS A SMALL CLOUD BUILDUP DIRECTLY IN FRONT OF US. THE BOTTOMS OF THESE BUILDUPS WERE AROUND 3200 FT MSL. AT THIS TIME, ATC ASKED US IF WE HAD THE ACFT IN FRONT IN SIGHT. THE CAPT ACKNOWLEDGED THE CTLR, BUT DID NOT RPT ACFT IN SIGHT. I WAS EXPECTING HIM TO CALL TFC IN SIGHT AND BE CLRED FOR THE VISUAL. I HAVE FLOWN INTO OGG NUMEROUS TIMES AND HAVE BEEN CLRED FOR THE VISUAL EVERY TIME. AT THIS TIME, MY SCAN WAS 95% OUTSIDE THE AIRPLANE. I WAS LOOKING AT THE ARPT, THE ACFT IN FRONT OF US AND THE CLOUD BUILDUP IN FRONT OF US THAT I WANTED TO AVOID. LOOKING BACK INTO THE COCKPIT, I NOTICED THE ALTIMETER READING AROUND 3000 FT. ATC THEN ASKED US WHAT OUR ALT WAS AND TOLD US TO MAINTAIN 3000 FT. HE THEN ASKED US IF WE HAD THE ARPT IN SIGHT AND CLRED US FOR THE VISUAL WHEN WE SAID YES. THE REST OF THE APCH AND LNDG WERE UNEVENTFUL. THE HUMAN FACTORS THAT LED UP TO THIS ALTDEV WERE: 1) HIGH COCKPIT ACTIVITY IN THE APCH PHASE WITHOUT THE AUTOPLT ON, 2) WANTING AND EXPECTING A VISUAL CLRNC TO AVOID A BUILDUP AND NOT ASKING FOR ONE OR GETTING ONE, ASSUMING THE CTLR WAS GOING TO GIVE IT TO US. SUPPLEMENTAL INFO FROM ACN 608364: MY FO SAID HE WOULD EXPEDITE HIS DSCNT TO AVOID A DECK OF CLOUDS. THESE CLOUDS LOOKED LIKE THEY WOULD GIVE US SOME PRETTY GOOD JOLTS. ATC GAVE US A HDG TO FLY AND POINTED OUT A HVY JET FOR US TO FOLLOW ON THE VISUAL APCH. I SAW THE JET, BUT BECAUSE I WAS NOT SURE IF WE COULD KEEP IT IN SIGHT AND BECAUSE I WANTED MORE SPACING FOR WAKE TURB AVOIDANCE, I DID NOT CALL THE JET IN SIGHT YET. MY FO THOUGHT THAT I DID CALL THE JET IN SIGHT AND THAT WE WERE CLRED FOR THE VISUAL APCH. HE DSNDED TO 3000 FT TO AVOID THE JOLTS. THIS RESULTED IN AN ALTDEV.

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.