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Potential less than standard separation between small aircraft X and air carrier Y. Ongoing situation: area of poor rdr coverage at pwm due to radar antenna obstruction.
| Attributes | |
| ACN | 156515 |
| Time | |
| Date | 199009 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : pwm |
| State Reference | ME |
| Altitude | msl bound lower : 5000 msl bound upper : 5000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : pwm artcc : zlc |
| Make Model Name | Small Aircraft, High Wing, 1 Eng, Fixed Gear |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : radar |
| Experience | controller radar : 7 |
| ASRS Report | 156515 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument |
| Events | |
| Anomaly | conflict : airborne less severe other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | Other |
| Miss Distance | horizontal : 18000 vertical : 1000 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | other |
| Situations | |
| Navigational Aid | Unspecified |
Narrative:
Because of an area of poor radar coverage west of pwm I had a tense moment when small aircraft X flying northeast along V39 at 5000' dropped off my scope. The problem was that I had started air carrier Y down out of 11000' to 4000' for the ILS to runway 11. When I first started air carrier Y down I could still see the small aircraft and was anticipating that air carrier Y would pass over him with a couple of thousand feet to spare, but when I looked back a min later and the small aircraft had dropped off, I began to second guess myself. Was the small aircraft still on the arwy? Even so was my first judgement correct because I could no longer monitor the sep. This radar problem is a bad situation. When will it be corrected? (A hotel was built near the antenna site!).
Original NASA ASRS Text
Title: POTENTIAL LESS THAN STANDARD SEPARATION BETWEEN SMA X AND ACR Y. ONGOING SITUATION: AREA OF POOR RDR COVERAGE AT PWM DUE TO RADAR ANTENNA OBSTRUCTION.
Narrative: BECAUSE OF AN AREA OF POOR RADAR COVERAGE W OF PWM I HAD A TENSE MOMENT WHEN SMA X FLYING NE ALONG V39 AT 5000' DROPPED OFF MY SCOPE. THE PROB WAS THAT I HAD STARTED ACR Y DOWN OUT OF 11000' TO 4000' FOR THE ILS TO RWY 11. WHEN I FIRST STARTED ACR Y DOWN I COULD STILL SEE THE SMA AND WAS ANTICIPATING THAT ACR Y WOULD PASS OVER HIM WITH A COUPLE OF THOUSAND FEET TO SPARE, BUT WHEN I LOOKED BACK A MIN LATER AND THE SMA HAD DROPPED OFF, I BEGAN TO SECOND GUESS MYSELF. WAS THE SMA STILL ON THE ARWY? EVEN SO WAS MY FIRST JUDGEMENT CORRECT BECAUSE I COULD NO LONGER MONITOR THE SEP. THIS RADAR PROB IS A BAD SITUATION. WHEN WILL IT BE CORRECTED? (A HOTEL WAS BUILT NEAR THE ANTENNA SITE!).
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.