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Air carrier flight crew reported being cleared for an rnp approach that they could not legally fly due to a rnp availability forecast (raf) .11 outage. Other crews were not aware of the NOTAM and this crew had difficulty convincing ATC that an ILS approach was required.
| Attributes | |
| ACN | 1332291 |
| Time | |
| Date | 201602 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Large Transport |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Not Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 142 |
| Person 2 | |
| Function | Pilot Flying Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 146 Flight Crew Type 7000 |
| Events | |
| Anomaly | ATC Issue All Types Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence |
Narrative:
On arrival approach held us due to poor weather. After being released from holding; we were at the front of the train for approach. Current ATIS was calling for 3/4 SM visibility with -sn. Upon checking the rnp availability forecast (raf); we discovered that 0.11 was north/a for a 30 minute window that was just beginning; and it would certainly be in effect throughout the duration of our approach and landing. Approach then cleared us for the RNAV (rnp) Y approach. Looking at the approach plate; the visibility minimums are RVR 50 or 1 SM for rnp 0.11; however; minimums are 1 1/4 SM for rnp 0.18 which is all the raf supported flying for this 30-minute window.I queried approach about the visibility to which the controller replied that it was 'one mile.' I responded that we needed 1 1/4 SM to legally fly the RNAV Y approach based on the raf; and he didn't seem to understand what I was referring to. At that time; another company crew stated 'you must be looking at the RNAV Z; he wants the RNAV Y' which was incorrect. The RNAV Z is a GPS approach; not an rnp approach; and we didn't have the weather to fly it even if we wanted to. After several exchanges with approach in which I was adamant that we needed 1 1/4 SM to fly the RNAV (rnp) Y approach; he recleared us (and the arrival train behind us) for the ILS.perhaps this is already an ATC procedure; I don't know; but perhaps approach should view and understand the raf prior to clearing aircraft for approaches that they cannot legally fly.
Original NASA ASRS Text
Title: Air carrier flight crew reported being cleared for an RNP approach that they could not legally fly due to a RNP Availability Forecast (RAF) .11 outage. Other crews were not aware of the NOTAM and this crew had difficulty convincing ATC that an ILS approach was required.
Narrative: On arrival Approach held us due to poor weather. After being released from holding; we were at the front of the train for approach. Current ATIS was calling for 3/4 SM visibility with -SN. Upon checking the RNP Availability Forecast (RAF); we discovered that 0.11 was N/A for a 30 minute window that was just beginning; and it would certainly be in effect throughout the duration of our approach and landing. Approach then cleared us for the RNAV (RNP) Y approach. Looking at the approach plate; the visibility minimums are RVR 50 or 1 SM for RNP 0.11; however; minimums are 1 1/4 SM for RNP 0.18 which is all the RAF supported flying for this 30-minute window.I queried Approach about the visibility to which the Controller replied that it was 'one mile.' I responded that we needed 1 1/4 SM to legally fly the RNAV Y Approach based on the RAF; and he didn't seem to understand what I was referring to. At that time; another company crew stated 'you must be looking at the RNAV Z; he wants the RNAV Y' which was incorrect. The RNAV Z is a GPS Approach; not an RNP Approach; and we didn't have the weather to fly it even if we wanted to. After several exchanges with Approach in which I was adamant that we needed 1 1/4 SM to fly the RNAV (RNP) Y Approach; he recleared us (and the arrival train behind us) for the ILS.Perhaps this is already an ATC procedure; I don't know; but perhaps Approach should view and understand the RAF prior to clearing aircraft for approaches that they cannot legally fly.
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.