Date: 201507
Local time of day: 1201-1800
Location: LGA.Airport, NY
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight phase: Landing
Airspace: Class B LGA
ATC / advisory: TRACON N90
Aircraft component: Autopilot
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction
Second reporter function: Captain; Pilot Flying
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Unstabilized Approach
Detector: Person Air Traffic Control; Person Flight Crew
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; Flight Crew Returned To Clearance
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Flight was cleared the visual 31 to LGA and approaching DIALS the Captain recognized that he had too much energy and attempted to correct the profile by lowering the gear and flaps as appropriate. Once established on final; he determined that we were too high to make a normal landing and directed a go-around. Tower directed us to climb to 1;000 feet to avoid another aircraft overflying the field and switched us to Approach and we complied. About the time of the radio switch; we leveled at 1;000 feet and the Captain engaged the autopilot. Upon checking in with Approach Control; we were instructed to turn to a 340 heading and climb and maintain 3;000 feet. I visually verified the Captain selecting 340 heading and 3;000 feet in the MCP however I did not visually verify that the heading mode was selected. We began a right turn and a climb and began setting up to prepare for another visual approach by loading the FMC. At this time; ATC asked if we were on a 340 heading and I looked at our heading passing roughly a 095 heading still in a right turn. I replied that we had missed our heading and asked ATC what heading he would like us to fly; and was instructed to fly a 090 heading. Once established on the 090 heading; the rest of the climb out and subsequent visual approach were uneventful. Once we had landed; the Captain and I discussed what had occurred and both agreed that the correct 340 heading had been selected in the MCP; and the Captain thought that we must have been in Control Wheel Steering (CWS) which would explain why we turned through our assigned heading. Strict adherence to the CRM principles would have ensured that we had selected Heading Select for our lateral control mode and through monitoring; would have trapped and corrected the error.Once I saw the 340 heading selected in the heading window and observed the aircraft start a right turn in the correct direction; I assumed that we were in heading mode without verifying and monitoring; resulting in overshooting the assigned heading. I believe both the Captain and myself were pushed out of the green by a challenging visual approach followed by an unplanned go-around. I believe the situation would have been avoided if we had slowed down; strictly followed procedures; and not been in a rush to get set up for the next approach.


Second narrative: On go-around from Runway 31 at LGA; we had already cleaned up and leveled on runway heading and 1;000 feet MSL. Departure gave us a turn to 340 degrees and a climb to 3;000 feet MSL. Aircraft was back in autopilot so I dialed in 340 degrees and 3;000 feet in altitude and started climb with Vertical Speed and turn with Heading Select. I started putting the arrival back into the FMC. Departure then asked us what heading we were going to and we then realized we had gone well past the 340 heading. Departure then told us to head 090 degrees which we did. The First Officer (FO) and I do not know when or how we had dropped out of Heading Select and gone to Control Wheel Steering (CWS). We were vectored back into sequence and landed. I should have continued flying and directed the FO to input the runway for the new approach.


Synopsis: B737 flight crew experienced an unstabilized approach during the Visual to Runway 31 at LGA and goes around. The crew levels at 1;000 feet on runway heading and is then instructed to climb to 3;000 feet and head 340 degrees. The climb and turn are initiated; but heading select is never engaged resulting in a turn to 095 degrees before ATC questioned the heading.