Date: 201701
Local time of day: 0601-1200
Location: BLI.Airport, WA
Flight conditions: VMC
Weather elements / visibility: Haze / Smoke
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: FBO
Operating under: Part 91
Flight plan: IFR
Mission: Training
Flight phase: Climb; Final Approach
Airspace: Class D BLI
ATC / advisory: TRACON CYYJ; Tower BLI
Reporter organization: FBO
Reporter function: Instructor; Pilot Not Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument
Human factors: Communication Breakdown; Confusion
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Executed Go Around / Missed Approach
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: My student and I were on an IFR clearance; on course and glide path for the BLI ILS RWY 16 final approach segment in simulated IFR conditions; in hazy VMC; overcast at approximately 5;000. There were two VFR airplanes in the vicinity; under control of the BLI tower. Victoria Terminal instructed my student (pilot flying) to contact Bellingham tower; he changed frequency and reported that we were inbound on the ILS 16. Tower asked us for our distance from the runway; I signaled my student that we were four miles out (GPS distance was a little more than 4 NM). The tower then issued instructions to the other two airplanes that seemed to me intended to provide separation before he cleared them behind us. Initially it seemed to me that he was considering sending one of them in front of us; considering our distance from the runway; tower had also asked my student for our speed; if I recall correctly. One of the VFR airplanes was instructed to execute a 'tight 360' and re-enter the base leg for Runway 16. Victoria Terminal had instructed us to execute the published missed approach; PF told Victoria Terminal that after the missed approach we wanted vectors to return to ZZZ; the next destination on our IFR clearance following BLI. We were not instructed to execute the KIENO Five DP; but assumed vectoring during execution of the missed approach that would send us if not to the KIENO intersection; then to the Penn Cove (CVV) VOR.On short final; the tower told us to 'start your turn over the numbers'; which we interpreted to mean to initiate the missed approach turn to 275 at the MAP instead of climbing to 700 ft before starting the turn. I assumed that the tower wanted to get us out of the way of the other traffic that wanted to land at BLI. We executed the turn as instructed; expecting a subsequent instruction to contact Victoria Terminal on reporting execution of the missed approach; climbing and turning to 275. After a short period; we were told by the tower to fly runway heading and we turned to 160; continuing the climb. I assumed that the tower was having us fly in a direction that would enable interception of the published missed course of 275; having achieved an offset to the west that provided separation for the landing traffic. I was expecting a 'hand off' to Victoria Terminal for the vectors that would get us back onto the published missed approach when the tower asked us if we wanted to continue or be handed back to Victoria Terminal. My student responded (incorrectly) that we wanted to return to ZZZ. Because we were still on an IFR clearance; he should have told the tower we wanted to be handed-off to Victoria Terminal. The tower then told us to turn 'south east which will pass you across the extended centerline for runway 16' (a paraphrase). My student interpreted this to mean that we were cleared to proceed direct to ZZZ. I was still expecting the handoff to Terminal. The tower then became concerned about our course; directed us to turn to 250; then 270; and to contact Victoria Terminal. We had been climbing throughout these maneuvers on the way to 5;000 ft. I can't recall if the tower issued the altitude instruction or if Victoria Terminal made the assignment when we checked in; Terminal may have also made the assignment to 270. Victoria Terminal asked if we had a moment 'to talk'. At that point we were stabilized in a climb to 5;000 on the assigned course of 270; effectively back on the missed approach. Victoria Terminal asked us to explain what had just happened. I said that we'd been instructed to start our turn over the numbers; then had been issued vectors by the tower for traffic avoidance; and then were instructed to fly 250 (and I think 270; but that may have been the initial vector after contacting Victoria Terminal). Victoria Terminal told us we had been instructed to fly the published missed approach and that the tower was listening to my explanation. VT subsequently said that we should haverequested clarification when we received the vectors that modified its original instruction to fly the published missed approach. I agreed and apologized for any confusion on our part.I was never told whether we had responded to instructions intended for or issued to other traffic or had misunderstood the vectors that had been issued to us. My student promptly read back all vectors that we thought were issued to our flight. We weren't corrected after any read back. I'd hoped to listen to a recording of the radio traffic on LiveATC.net to review what I thought we'd been told and determine how we might have misunderstood the vectors; but BLI traffic isn't recorded by this service.The major lesson learned for me is to request clarification or confirmation (even after a read back) for any instruction that modifies a missed approach procedure after initiating execution. While we did not see the other traffic; I don't believe that there was a conflict. It seemed to me that the other traffic was behind us; in the course of receiving vectors to join the pattern as VFR traffic. The day was hazy with an overcast.




Synopsis: C172 instructor reported confusion with their clearance while initiating the missed approach on the BLI Runway 16 ILS. After BLI Tower handed them off to Victoria Terminal; they are questioned on why they did not fly the published missed approach as earlier instructed by Victoria Terminal.