|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||atc facility : zoa|
|Affiliation||government : faa|
|Function||controller : radar|
|Qualification||controller : radar|
|Anomaly||other anomaly other|
|Independent Detector||other controllera|
|Resolutory Action||none taken : unable|
|Air Traffic Incident||other|
Natca has received several reports in the last yr that have involved operational errors in which the air traffic controller involved was idented as the cause of the error. These errors all deal with a loss of separation of either vertical or lateral separation standards. The common factors involved in these errors are the controller has allowed the aircraft to become very close to losing standard separation and has taken actions to insure separation and the aircraft involved are TCASII equipped. In each of these errors the pilots were receiving RA's. The pilots respond to the RA provided by TCASII and not the control instructions given by ATC. In each of these sits, natca feels if the pilot had complied with the controller's instructions a loss of separation may not have occurred. The aim and FARS require the pilot to respond to ATC instructions, unless, in the pilot's judgement, aircraft safety will be compromised or an emergency situation exists. The pilot is additionally required by law to respond to an RA, and lastly company policy may require that the pilot comply with the RA before complying with ATC instructions. If a pilot is receiving instructions from TCASII and instructions from ATC simultaneously, the pilot is required to follow TCASII instructions and not ATC instructions. FAA order 7110.65 J states when an aircraft under your control jurisdiction informs you that it is responding to a TCASII RA do not issue control instructions that are contrary to the RA the crew has advised you that they are executing. Several questions arise with this rule. Pilot to controller communications has never been clear as to when a pilot and what a pilot states to the controller. FAA order 7110.65 suggests a pilot use a certain verbiage but makes no requirement on the pilot to notify ATC the exact maneuver taking place. This leaves the controller in a guessing game. Another question that must be addressed is when does the pilot become responsible for separation between his aircraft and other aircraft he may be in conflict with and when does the controller's responsibility end? FAA order 7110.65 states that once the responding aircraft has begun a maneuver in response to an RA, the controller is not responsible for providing standard separation between the aircraft that is responding to an RA and any other aircraft, airspace, terrain or obstruction. There is no established procedure that can be used to determine when the responding aircraft has begun a maneuver in response to an RA. Natca feels it is imperative to address pilot to controller communications during an RA event as a matter of safety. This subject has long been left unexplored because of the potential seriousness of the subject. Additionally, there must be a procedure in place that will allow the controllers to know when they are no longer responsible for separation.
Original NASA ASRS Text
Title: CTLR STATES THAT NO SPECIFIC REQUIREMENT FOR ACFT TO INFORM ATC WHEN EXECUTING A TCASII RA MANEUVER. CTLR IS RESPONSIBLE FOR SEPARATION UNTIL INFORMED OF AN ACFT MANEUVER.
Narrative: NATCA HAS RECEIVED SEVERAL RPTS IN THE LAST YR THAT HAVE INVOLVED OPERATIONAL ERRORS IN WHICH THE AIR TFC CTLR INVOLVED WAS IDENTED AS THE CAUSE OF THE ERROR. THESE ERRORS ALL DEAL WITH A LOSS OF SEPARATION OF EITHER VERT OR LATERAL SEPARATION STANDARDS. THE COMMON FACTORS INVOLVED IN THESE ERRORS ARE THE CTLR HAS ALLOWED THE ACFT TO BECOME VERY CLOSE TO LOSING STANDARD SEPARATION AND HAS TAKEN ACTIONS TO INSURE SEPARATION AND THE ACFT INVOLVED ARE TCASII EQUIPPED. IN EACH OF THESE ERRORS THE PLTS WERE RECEIVING RA'S. THE PLTS RESPOND TO THE RA PROVIDED BY TCASII AND NOT THE CTL INSTRUCTIONS GIVEN BY ATC. IN EACH OF THESE SITS, NATCA FEELS IF THE PLT HAD COMPLIED WITH THE CTLR'S INSTRUCTIONS A LOSS OF SEPARATION MAY NOT HAVE OCCURRED. THE AIM AND FARS REQUIRE THE PLT TO RESPOND TO ATC INSTRUCTIONS, UNLESS, IN THE PLT'S JUDGEMENT, ACFT SAFETY WILL BE COMPROMISED OR AN EMER SIT EXISTS. THE PLT IS ADDITIONALLY REQUIRED BY LAW TO RESPOND TO AN RA, AND LASTLY COMPANY POLICY MAY REQUIRE THAT THE PLT COMPLY WITH THE RA BEFORE COMPLYING WITH ATC INSTRUCTIONS. IF A PLT IS RECEIVING INSTRUCTIONS FROM TCASII AND INSTRUCTIONS FROM ATC SIMULTANEOUSLY, THE PLT IS REQUIRED TO FOLLOW TCASII INSTRUCTIONS AND NOT ATC INSTRUCTIONS. FAA ORDER 7110.65 J STATES WHEN AN ACFT UNDER YOUR CTL JURISDICTION INFORMS YOU THAT IT IS RESPONDING TO A TCASII RA DO NOT ISSUE CTL INSTRUCTIONS THAT ARE CONTRARY TO THE RA THE CREW HAS ADVISED YOU THAT THEY ARE EXECUTING. SEVERAL QUESTIONS ARISE WITH THIS RULE. PLT TO CTLR COMS HAS NEVER BEEN CLR AS TO WHEN A PLT AND WHAT A PLT STATES TO THE CTLR. FAA ORDER 7110.65 SUGGESTS A PLT USE A CERTAIN VERBIAGE BUT MAKES NO REQUIREMENT ON THE PLT TO NOTIFY ATC THE EXACT MANEUVER TAKING PLACE. THIS LEAVES THE CTLR IN A GUESSING GAME. ANOTHER QUESTION THAT MUST BE ADDRESSED IS WHEN DOES THE PLT BECOME RESPONSIBLE FOR SEPARATION BTWN HIS ACFT AND OTHER ACFT HE MAY BE IN CONFLICT WITH AND WHEN DOES THE CTLR'S RESPONSIBILITY END? FAA ORDER 7110.65 STATES THAT ONCE THE RESPONDING ACFT HAS BEGUN A MANEUVER IN RESPONSE TO AN RA, THE CTLR IS NOT RESPONSIBLE FOR PROVIDING STANDARD SEPARATION BTWN THE ACFT THAT IS RESPONDING TO AN RA AND ANY OTHER ACFT, AIRSPACE, TERRAIN OR OBSTRUCTION. THERE IS NO ESTABLISHED PROC THAT CAN BE USED TO DETERMINE WHEN THE RESPONDING ACFT HAS BEGUN A MANEUVER IN RESPONSE TO AN RA. NATCA FEELS IT IS IMPERATIVE TO ADDRESS PLT TO CTLR COMS DURING AN RA EVENT AS A MATTER OF SAFETY. THIS SUBJECT HAS LONG BEEN LEFT UNEXPLORED BECAUSE OF THE POTENTIAL SERIOUSNESS OF THE SUBJECT. ADDITIONALLY, THERE MUST BE A PROC IN PLACE THAT WILL ALLOW THE CTLRS TO KNOW WHEN THEY ARE NO LONGER RESPONSIBLE FOR SEPARATION.
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.