Air carrier flight crew reported non-compliance with the obstacle clearance charted procedure while climbing from a non-towered airport.
Synopsis
Air carrier flight crew reported non-compliance with the obstacle clearance charted procedure while climbing from a non-towered airport.
Narrative
ZZZ is uncontrolled. Once holding short of the runway; we called ZZZ Center and received our clearance to ZZZ1 via as filed. We had planned for the ZZZ obstacle departure; which reads to turn right direct to ZZZ VOR; then from ZZZ climb in hold until passing MEA/MCA. We were familiar with the terrain; had briefed the grid MORAs; had terrain radar on Navigation Display (ND); and had the enroute chart open. Weather was night VFR. After take-off; approaching the ZZZ VOR; we were identified by and in contact with ATC. We were climbing at a rate that [made it] clear that terrain separation wouldn't be an issue. We were approaching the MSA and so we decided we did not need to enter the hold; but rather to turn enroute as filed. We were of the mindset that once in contact and identified; that ATC would take over both terrain and route clearance/planning; but no further instructions were given. Out of curiosity; we queried ATC if they needed a specific altitude to continue on our route; or if they had a minimum vectoring altitude [that] they needed us to climb above. They reminded us that terrain separation was our responsibility at that time; but that if we had any doubt they recommended a heading of 170 degrees. While terrain separation was never in any doubt for us; in order to ensure we were all on the same page; we elected turn onto the suggested heading; and passing XY;000 we were cleared direct to ZZZ1 VOR and continued our flight as planned. In hindsight; we should have entered the hold at ZZZ [VOR] and competed the obstacle departure routing; including a climb to at least XX;200 ft. (MORA) and requested direct routing; or to XZ;000 ft. (airway MEA) and continued as filed. Terrain clearance was never in doubt; the radar altimeter never activated; and the terrain radar display gave us no cause for concern. The enroute chart was displayed; and MORAs were extensively briefed (since it was night and uncontrolled). However; in essence; we deviated from the obstacle departure procedure; and thus also deviated from the Operations Manual procedure; and felt it prudent to file this.
Second reporter narrative
We were cleared as filed to ZZZ1 departing ZZZ which is uncontrolled. We briefed the departure procedure ZZZ. Upon departure started on the Obstacle Departure Procedure (ODP) but elected not to do the hold as we felt we were safely approaching MSA and MORA. Our display and terrain display reflected so as well. We queried ATC on our terrain clearance and they advised terrain separation was our responsibility but advised a vector to the South. We took the vector and out of XY;000 proceeded direct to ZZZ1 [VOR]. In hindsight; per general operations manual we should have flown full ODP (entered hold) until ATC was satisfied to give us a direct or just continue to MEA until going on course. Clarifying clearance with my First Officer (FO). Proper operations manual adherence. Following ODP procedures.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.