Date: 201602
Local time of day: 1201-1800
Location: GEG.Airport, WA
Flight conditions: VMC
Weather elements / visibility: 30
Light: Daylight
Aircraft: Small Transport
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Cruise
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Other Person
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Diverted
Contributing factors: Procedure
Primary problem: Procedure

Narrative: I was operating as Pilot-in-Command of a privately-owned Part 91 flight from [the United States] to [an airport in] British Columbia to drop off my three passengers before ferrying the aircraft back to [a U.S. airport]. As per the international flight procedures; I had filed US CBP eAPIS manifests and ICAO flight plans for both the flight into Canada and the return flight back into the US. Additionally; I coordinated my arrival into Canada with Canadian Customs and landed [in British Columbia] with no issues. Upon my return flight to the US; I obtained my IFR clearance from Vancouver Center and was handed off to first Seattle Center during my US/Canada border crossing; and then later to Spokane Approach. After checking in with Spokane Approach; I was informed that; rather than continue to [the original destination] to clear Customs where I had intended; the US CBP was requesting that I instead clear Customs at Spokane International (GEG); with which I complied. Upon my shutdown in front of the US Customs office at GEG; I was very sternly informed that; in spite of my filing the appropriate eAPIS Arrival Manifest and ICAO Flight Plan; as well as obtaining my international IFR ATC Clearance; I hadn't received specific permission to enter US Airspace from the US CBP. I explained that it was my understanding that my eAPIS Arrival manifest and subsequent international IFR flight plan clearance had constituted permission and notification of my arrival into the US; which I was again told was incorrect. I spent upwards of 30 minutes then discussing with the Customs officer the preferred US CBP Arrival procedures; as well as the requirement for pilots to call and directly coordinate with the Customs office at the intended US Airport of Entry. After my extensive discussion with the officer; I now fully understand that the notification requirements of the individual Customs offices are independent of eAPIS filing notifications. However; in a fair amount of my after-the-fact reading and research; the absolute necessity of contacting the individual AOE Customs office isn't made particularly clear; nor is it clear that the eAPIS filing is not considered Customs notification. Usage of soft terminology wordings such as 'pilots SHOULD contact the CBP office' or 'CBP RECOMMENDS that flyers directly contact...'; as well as an unclear distinction between eAPIS filing and direct; over-the-phone Customs notification cloud the absolute requirement of directly contacting the CBP office independent of the eAPIS filing. Wording such as 'must' or 'required'; as well as standardized procedures between CBP offices; would've greatly diminished my incorrect understanding that eAPIS constituted the required Customs notification.




Synopsis: A general aviation pilot reported that after filing all known paperwork to return to the United States from Canada; the United States Customs Border Patrol advised that proper permission had not been requested and granted to enter US airspace.