Air carrier starts descent early while on a vector to intercept the LOCALIZE5R.

Attributes
ACN	145034
Time
Date	199005
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lga
State Reference	NY
Altitude	msl bound lower : 2000 msl bound upper : 3000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 7500 flight time type : 2000
ASRS Report	145035
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 95 flight time total : 16000
ASRS Report	144355
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On approach into lga, ILS 22, we were cleared to 3000'. At that point we received a SELCAL from company. The captain was flying, so I answered the call and was off frequency for about 1 min. When I returned to the approach frequency the controller was calling traffic at 1700', then questioned our altitude, which I still assumed our altitude was 3000', but the captain had descended down to 2000'. Our clearance was to maintain 3000' until yoman. The controller made comment about our altitude and 3000' until yoman. The captain said our vector was taking us inside of yoman for the intercept and we weren't going to actually cross yoman, so he started this descent. At that point we were already inside yoman and intercepting the localizer. We were at a critical phase of flight and with the distraction of the call from company we both were not watching what was going on. When a crossing restrictions is given and a subsequent vector puts you inside the restriction point. Can you descend, or must you wait until you are abeam the point? It seems to be a gray area.

Original NASA ASRS Text

Title: ACR STARTS DESCENT EARLY WHILE ON A VECTOR TO INTERCEPT THE LOCALIZE5R.

Narrative: ON APCH INTO LGA, ILS 22, WE WERE CLRED TO 3000'. AT THAT POINT WE RECEIVED A SELCAL FROM COMPANY. THE CAPT WAS FLYING, SO I ANSWERED THE CALL AND WAS OFF FREQ FOR ABOUT 1 MIN. WHEN I RETURNED TO THE APCH FREQ THE CTLR WAS CALLING TFC AT 1700', THEN QUESTIONED OUR ALT, WHICH I STILL ASSUMED OUR ALT WAS 3000', BUT THE CAPT HAD DSNDED DOWN TO 2000'. OUR CLRNC WAS TO MAINTAIN 3000' UNTIL YOMAN. THE CTLR MADE COMMENT ABOUT OUR ALT AND 3000' UNTIL YOMAN. THE CAPT SAID OUR VECTOR WAS TAKING US INSIDE OF YOMAN FOR THE INTERCEPT AND WE WEREN'T GOING TO ACTUALLY CROSS YOMAN, SO HE STARTED THIS DSNT. AT THAT POINT WE WERE ALREADY INSIDE YOMAN AND INTERCEPTING THE LOC. WE WERE AT A CRITICAL PHASE OF FLT AND WITH THE DISTR OF THE CALL FROM COMPANY WE BOTH WERE NOT WATCHING WHAT WAS GOING ON. WHEN A XING RESTRICTIONS IS GIVEN AND A SUBSEQUENT VECTOR PUTS YOU INSIDE THE RESTRICTION POINT. CAN YOU DSND, OR MUST YOU WAIT UNTIL YOU ARE ABEAM THE POINT? IT SEEMS TO BE A GRAY AREA.

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.