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Enroute controller described a loss of separation event listing the current 'time to climb' procedures as confusing and in need of revisions.
| Attributes | |
| ACN | 985103 |
| Time | |
| Date | 201112 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Aircraft 1 | |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | Enroute |
| Qualification | Air Traffic Control Fully Certified |
| Events | |
| Anomaly | ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Undershoot Deviation - Procedural Clearance |
Narrative:
A B737 checked on frequency at FL380 with discretionary descent to FL370. Descent was issued to FL350 with time restriction to be level at FL350 by 0304z. Time was issued to the pilot as required in 7110.65. Read back was complete. At approximately 0303:30z the pilot of the B737 was instructed to report level at FL350. At 0304z the aircraft had not reached level flight at FL350 and shortly afterward oedp activated indicating a loss of separation between the B737 and another B737. The total elapsed time from clearance issued and the B737 reaching FL350 was approximately 2 minutes and 15 to 20 seconds. The time to climb and/or descend clearance as currently required is cumbersome and prone to read back errors and misunderstandings. A simpler procedure should be put into place to decrease time on frequency needed to issue a time based altitude restriction.
Original NASA ASRS Text
Title: Enroute Controller described a loss of separation event listing the current 'time to climb' procedures as confusing and in need of revisions.
Narrative: A B737 checked on frequency at FL380 with discretionary descent to FL370. Descent was issued to FL350 with time restriction to be level at FL350 by 0304z. Time was issued to the pilot as required in 7110.65. Read back was complete. At approximately 0303:30z the pilot of the B737 was instructed to report level at FL350. At 0304z the aircraft had not reached level flight at FL350 and shortly afterward OEDP activated indicating a loss of separation between the B737 and another B737. The total elapsed time from clearance issued and the B737 reaching FL350 was approximately 2 minutes and 15 to 20 seconds. The time to climb and/or descend clearance as currently required is cumbersome and prone to read back errors and misunderstandings. A simpler procedure should be put into place to decrease time on frequency needed to issue a time based altitude restriction.
Data retrieved from NASA's ASRS site as of April 2012 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.