An air carrier first officer reported confusion when flying the mso RNAV-D approach after ATC cleare...

Narrative:

Initially we briefed the ILS approach to runway 11 as our briefing. We then were able to receive the verbal ATIS and changed to brief the RNAV-D approach since the runway in use was 29. During descent we were given an instruction by ATC to descend and maintain 13000 ft. Later we were given an instruction 'cleared from ubijo direct botby then missoula airport.' in the FMS the captain/PF (pilot flying) entered botby on top of stacc to delete the stacc intersection resulting in a course direct from ubijo to botby. This was confirmed by myself as we both took this to be the correct method to accomplish the clearance as given by ATC. After a few more minutes we were then cleared by ATC to fly the profile of the RNAV-D approach. This was where the confusion set in. We both took this to be a sort of approach clearance and proceeded to fly the rest of the approach as published. At this point we had descended to an altitude of 10;300 feet. We had deleted the stacc fix which resulted in us being unaware if we were above the 11300 ft MEA on the approach but were then queried by ATC as to our altitude. I responded with our current altitude and received no response. I tried back 3 times and then changed to spokane approach hoping to hear from them. After no response there as well; I tried center on the published frequency (not what our original center frequency was) 133.4 and received a response. They again queried our altitude; I again responded; and then the controller paused and gave us an approach clearance. He stated we were cleared for the RNAV approach to missoula. He then handed us off to spokane approach where the controller again queried our altitude; I again responded and then stated we were cleared for the RNAV-D by center. The controller didn't say any more and later handed us to tower where we landed uneventfully. Following botby we were officially cleared for the approach and flew the altitudes as published.after the controller queried our altitude we took a second look at our plates and both decided we probably had some sort of altitude deviation and hence the reason we might have had trouble receiving their radio calls.the root cause of this event was a loss of situational awareness due to misleading and non-standard ATC phraseology. Normally we would have received a clearance to maintain an altitude until a fix and cleared for the approach rather than the terminology the controller used to request us to fly the profile of the approach. I took profile to mean lateral only; while the captain took it to mean vertical and lateral.ATC should have used more proper phraseology or cleared us for the approach and verified we were to maintain 13000 ft until a specific waypoint. We also should have clarified the approach clearance initially when we received a non-standard clearance. I personally also should have clarified with the captain what altitude he was planning on flying and at what point he planned to descend to the published altitudes to confirm his intentions with my understanding of the ATC clearance.

Original NASA ASRS Text

Title: An air carrier First Officer reported confusion when flying the MSO RNAV-D approach after ATC cleared the flight UBIJO direct BOTBY. Because the STACC waypoint was deleted; the flight descended to 10;300 ft which is below the STACC 11;300 ft MEA.

Narrative: Initially we briefed the ILS approach to Runway 11 as our briefing. We then were able to receive the verbal ATIS and changed to brief the RNAV-D approach since the runway in use was 29. During descent we were given an instruction by ATC to descend and maintain 13000 ft. Later we were given an instruction 'Cleared from UBIJO direct BOTBY then Missoula Airport.' In the FMS the Captain/PF (Pilot Flying) entered BOTBY on top of STACC to delete the STACC intersection resulting in a course direct from UBIJO to BOTBY. This was confirmed by myself as we both took this to be the correct method to accomplish the clearance as given by ATC. After a few more minutes we were then cleared by ATC to fly the profile of the RNAV-D approach. This was where the confusion set in. We both took this to be a sort of approach clearance and proceeded to fly the rest of the approach as published. At this point we had descended to an altitude of 10;300 feet. We had deleted the STACC fix which resulted in us being unaware if we were above the 11300 ft MEA on the approach but were then queried by ATC as to our altitude. I responded with our current altitude and received no response. I tried back 3 times and then changed to Spokane approach hoping to hear from them. After no response there as well; I tried center on the published frequency (not what our original center frequency was) 133.4 and received a response. They again queried our altitude; I again responded; and then the controller paused and gave us an approach clearance. He stated we were cleared for the RNAV approach to Missoula. He then handed us off to Spokane approach where the controller again queried our altitude; I again responded and then stated we were cleared for the RNAV-D by center. The controller didn't say any more and later handed us to tower where we landed uneventfully. Following BOTBY we were officially cleared for the approach and flew the altitudes as published.After the controller queried our altitude we took a second look at our plates and both decided we probably had some sort of altitude deviation and hence the reason we might have had trouble receiving their radio calls.The root cause of this event was a loss of situational awareness due to misleading and non-standard ATC phraseology. Normally we would have received a clearance to maintain an altitude until a fix and cleared for the approach rather than the terminology the controller used to request us to fly the profile of the approach. I took profile to mean lateral only; while the captain took it to mean vertical and lateral.ATC should have used more proper phraseology or cleared us for the approach and verified we were to maintain 13000 ft until a specific waypoint. We also should have clarified the approach clearance initially when we received a non-standard clearance. I personally also should have clarified with the captain what altitude he was planning on flying and at what point he planned to descend to the published altitudes to confirm his intentions with my understanding of the ATC clearance.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1403939
Time
Date	201611
Local Time Of Day	1201-1800
Place
Locale Reference	ZLC.ARTCC
State Reference	UT
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Deviation - Altitude Overshoot Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance

An air carrier first officer reported confusion when flying the mso RNAV-D approach after ATC cleared the flight ubijo direct botby. Because the stacc waypoint was deleted; the flight descended to 10;300 ft which is below the stacc 11;300 ft MEA.