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Controller clears 2 aircraft to higher altitude. First aircraft is slow clber and second aircraft catches up resulting in less than standard separation.
| Attributes | |
| ACN | 214337 |
| Time | |
| Date | 199206 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zdc |
| State Reference | DC |
| Altitude | msl bound lower : 25000 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport |
| Navigation In Use | Other |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| ASRS Report | 214337 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation non adherence : published procedure non adherence : far other anomaly other |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance |
| Consequence | Other |
| Miss Distance | horizontal : 27000 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Pilot Deviation Operational Error |
Narrative:
Climbed air carrier X to FL270 (he was leaving FL240). Air carrier Y a FL220 was crossing air carrier X and was directed to FL250. I noticed air carrier X was climbing too slow for separation and told air carrier Y to stop climb at FL230. No answer. I told air carrier Y again to stop at FL230. No answer. I told air carrier X to expedite to FL270. I told air carrier Y to stop at FL240. No answer and again told air carrier Y to stop at FL240. No answer. I lost separation. Finally, I got air carrier Y and descended him to FL240 and turned air carrier X to heading 090. Air carrier X was just reaching FL250. I was busy and frequency congestion was the reason he said he didn't get any of my clrncs. He told me I kept getting blocked on my xmissions. Also the extremely slow climb rate of air carrier X contributed to it. Suggestions: tell all aircraft to maintain radio silence when possible when frequency congestion problems occurs. Ladder aircraft under each other not betting that you can talk to the aircraft when you want (no matter how many times you transmit). Use vertical until you get lateral.
Original NASA ASRS Text
Title: CTLR CLRS 2 ACFT TO HIGHER ALT. FIRST ACFT IS SLOW CLBER AND SECOND ACFT CATCHES UP RESULTING IN LTSS.
Narrative: CLBED ACR X TO FL270 (HE WAS LEAVING FL240). ACR Y A FL220 WAS XING ACR X AND WAS DIRECTED TO FL250. I NOTICED ACR X WAS CLBING TOO SLOW FOR SEPARATION AND TOLD ACR Y TO STOP CLB AT FL230. NO ANSWER. I TOLD ACR Y AGAIN TO STOP AT FL230. NO ANSWER. I TOLD ACR X TO EXPEDITE TO FL270. I TOLD ACR Y TO STOP AT FL240. NO ANSWER AND AGAIN TOLD ACR Y TO STOP AT FL240. NO ANSWER. I LOST SEPARATION. FINALLY, I GOT ACR Y AND DSNDED HIM TO FL240 AND TURNED ACR X TO HDG 090. ACR X WAS JUST REACHING FL250. I WAS BUSY AND FREQ CONGESTION WAS THE REASON HE SAID HE DIDN'T GET ANY OF MY CLRNCS. HE TOLD ME I KEPT GETTING BLOCKED ON MY XMISSIONS. ALSO THE EXTREMELY SLOW CLB RATE OF ACR X CONTRIBUTED TO IT. SUGGESTIONS: TELL ALL ACFT TO MAINTAIN RADIO SILENCE WHEN POSSIBLE WHEN FREQ CONGESTION PROBLEMS OCCURS. LADDER ACFT UNDER EACH OTHER NOT BETTING THAT YOU CAN TALK TO THE ACFT WHEN YOU WANT (NO MATTER HOW MANY TIMES YOU XMIT). USE VERT UNTIL YOU GET LATERAL.
Data retrieved from NASA's ASRS site as of July 2007 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.