Date: 201404
Local time of day: 1801-2400
Location: N90.TRACON, NY
Flight conditions: Mixed
Weather elements / visibility: 6
Light: Night
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B LGA
ATC / advisory: Center ZNY; TRACON N90
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Time Pressure; Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Airport; Aircraft; Human Factors; Procedure
Primary problem: Ambiguous

Narrative: I was pilot monitoring.  We were having problems with ACARS getting ATIS.  It wasn't until we were relatively close to the field that we got ATIS.   During the descent; New York Center was placing aircraft in the hold on the arrival.  We were instructed to hold.  Literally; as we hit the holding fix; ATC canceled the hold and we were told to resume the STAR with speed restrictions.  Our initial plan/brief was to land Runway 22 at LGA.  When we finally received ATIS; we were expecting the ILS Runway 04 circle to land Runway 22. This in and of itself is a bit confusing as I had never heard of doing a precision approach to a circle maneuver. I had been to LGA two weeks previously; however; it was during the day.  During night conditions; the field is nearly impossible to pick up with all the city and ambient lighting; especially if you haven't been there at night/nor familiar with the field.  During the descent; ATC said to expect ILS Runway 04 Circle 31 this was different than what we had prepared for in the ILS Runway 04 Circle 22.   ATC was extremely congested at the time.   We had the raw data setup for the ILS to Runway 04 and backed up by the Localizer 31.  The Captain had loaded the Localizer to 31 in the FMC to enhance our SA.  ATC then cleared us the ILS Runway 04 Circle to 31. They never provided circling direction as to whether we were to circle south for a left base 31 or circle north for a right base to 31.  As we started the approach; we were both outside attempting to acquire the field. On the precision to Runway 04; I saw the approach lights; called the field; but as we turned to the east; I completely lost sight of the field and continued to stay outside in an effort to reacquire the field.  As we widened our pattern; New York Approach advised us of JFK traffic and we were outside of the circling approach airspace.  ATC then gave us a vector toward the field and climb out instructions.  We were re-vectored to the approach and re-attempted the same maneuver and landed without further incident. Due to the ever changing ATC/runway in use; we were rushed in the arrival circle approach.   It wasn't till later that we noticed that DME for the ILS is off the VOR so you have to cross tune DME for raw data. I could have been more proactive and placed a 3.4 mile circle on the Fix page and that would have helped us stay within the circling airspace. Fly the approach (ILS 04) as if we were in IMC conditions and then drone in till we were 100% sure we had the field.  Then square our corner to enter a left downwind for Runway 31.  However; I don't believe that is the intention of NY Approach; as they were trying to sequence in as many aircraft as the Tower could handle.   So; in the effort of trying to help ATC; we hosed ourselves. A more thorough brief on the ILS Runway 04 and then driving in till we were both 100% sure we had the field. We started circling approach outside circling parameters.


Second narrative: Problems began before Top of Descent. ACARS did not work; so we received ATIS later than normal. Briefed our initial plan to land Runway 22 at LGA off of ATIS on the weather packet. When we received ATIS; we changed that plan to comply; and briefed ILS to Runway 4; circle to land Runway 22. Subsequent ATIS changed this to ILS Runway 4; circle to land Runway 31. As we began to brief this; we were given holding instructions; so briefing was incomplete. It was my first time to LGA; and my First Officer's first time at night. We captured Localizer for Runway 4 and began to look for the field. I (pilot flying); had the Runway 4 Localizer selected; with the Runway 31 Localizer in the standby NAV; so I could switch during approach; as rain showers were intermittent and sometimes obscuring visibility. I did not brief the First Officer to have the LGA VOR selected; which was a mistake; since that is the DME source for the Runway 4 approach. We had a Runway 31 approach loaded in the FMC to help with final approach SA. We thought we had a visual on the field; and I began a circling turn and a descent based on that visual. However; once we turned; the rain and many city lights caused us to lose that visual. I was now pointed at a three-mile final to Runway 31; based off of the approach we had loaded in the FMC; and we were both attempting to re-acquire the field. At that point; Approach called out JFK traffic which we had in sight; and stated that we were not in circling airspace. They gave a vector back toward the field and a climb. We were vectored back to the approach and landed without incident. After landing; we found it very difficult to navigate to Gate because of signage and poor lighting.One error was not briefing the First Officer to have the LGA VOR tuned for DME SA. This; or loading the Runway 4 FAF into the LEGS page; would have given me definite parameters on where to begin the circle. It would also help if the LGA Runway 4 ILS freq had DME information. I should not have begun the circling maneuver without absolute certainty of visual of the airport; backed up with DME. Since it was my first time landing at LGA; and my F/O's first time landing there at night; I was trying to ensure we had adequate room to maneuver to land; but apparently I turned too early. Once we realized we did not have visual of the field; we should have alerted ATC and requested a vector; or executed a go-around. This would have been difficult due to the extremely busy ATC frequency; but would have been the correct choice. Gate at LGA has poor signage. When turning from Taxiway B to J; it is very difficult to see which gate is X; especially at nit.


Synopsis: B737 flight crew reports difficulty complying with a circle to land clearance at LGA resulting in ATC issuing a climb and vectors for another approach. It was night with rain showers and the crew was new to the airport. The second attempt was successful.