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Change to controller handbook drops requirement for VFR code display.
| Attributes | |
| ACN | 326529 |
| Time | |
| Date | 199601 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : ztl |
| State Reference | GA |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 14 |
| ASRS Report | 326529 |
| Events | |
| Anomaly | other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | none taken : unable |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Navigational Facility |
| Air Traffic Incident | other |
Narrative:
Until recently, under the paragraph 5-2-14. Code monitor, of the 7110.65, controllers were required to monitor the beacon codes 1200 and 4000. This requirement has recently been dropped. I believe this new policy to be a serious error in judgement and potentially a very serious threat to safety. If a VFR target displaying a mode C readout is below the altitude limits set at a particular sector, the target is not displayed on the radar scope. While this is fine at or above FL180 (class a airspace) it could be a very serious safety problem at 17500 ft and below. My research indicates that a pilot has no way of knowing if a transponder is displaying an inaccurate mode C readout unless he verifies the readout with ATC. For example, a pilot is flying at 11500 ft believing that his transponder is functioning properly. However, his mode C is indicating his altitude is 8500 ft. At a sector with the altitude limits set at 9800 ft through 24200 ft (as most sectors in ZTL) the controller would never be aware of the aircraft. The computer, in effect, verifies a non-verified mode C and does not display the aircraft. Therefore, the controller cannot issue advisories on this aircraft, whose altitude is unknown, to any conflicting traffic. I believe that the requirement to enter the beacon codes 1200 and 4000 in the beacon list of the r-side crd should be reinstated immediately.
Original NASA ASRS Text
Title: CHANGE TO CTLR HANDBOOK DROPS REQUIREMENT FOR VFR CODE DISPLAY.
Narrative: UNTIL RECENTLY, UNDER THE PARAGRAPH 5-2-14. CODE MONITOR, OF THE 7110.65, CTLRS WERE REQUIRED TO MONITOR THE BEACON CODES 1200 AND 4000. THIS REQUIREMENT HAS RECENTLY BEEN DROPPED. I BELIEVE THIS NEW POLICY TO BE A SERIOUS ERROR IN JUDGEMENT AND POTENTIALLY A VERY SERIOUS THREAT TO SAFETY. IF A VFR TARGET DISPLAYING A MODE C READOUT IS BELOW THE ALT LIMITS SET AT A PARTICULAR SECTOR, THE TARGET IS NOT DISPLAYED ON THE RADAR SCOPE. WHILE THIS IS FINE AT OR ABOVE FL180 (CLASS A AIRSPACE) IT COULD BE A VERY SERIOUS SAFETY PROB AT 17500 FT AND BELOW. MY RESEARCH INDICATES THAT A PLT HAS NO WAY OF KNOWING IF A XPONDER IS DISPLAYING AN INACCURATE MODE C READOUT UNLESS HE VERIFIES THE READOUT WITH ATC. FOR EXAMPLE, A PLT IS FLYING AT 11500 FT BELIEVING THAT HIS XPONDER IS FUNCTIONING PROPERLY. HOWEVER, HIS MODE C IS INDICATING HIS ALT IS 8500 FT. AT A SECTOR WITH THE ALT LIMITS SET AT 9800 FT THROUGH 24200 FT (AS MOST SECTORS IN ZTL) THE CTLR WOULD NEVER BE AWARE OF THE ACFT. THE COMPUTER, IN EFFECT, VERIFIES A NON-VERIFIED MODE C AND DOES NOT DISPLAY THE ACFT. THEREFORE, THE CTLR CANNOT ISSUE ADVISORIES ON THIS ACFT, WHOSE ALT IS UNKNOWN, TO ANY CONFLICTING TFC. I BELIEVE THAT THE REQUIREMENT TO ENTER THE BEACON CODES 1200 AND 4000 IN THE BEACON LIST OF THE R-SIDE CRD SHOULD BE REINSTATED IMMEDIATELY.
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.