JFK B757 VS B747 Wake Encounter

[Guest B1900 Mech]

ACN: 558222TimeDate : 200208Day : MonLocal Time Of Day : 1801 To 2400PlaceLocale Reference.Airport : JFK.AirportState Reference : NYAircraft / 1Controlling Facilities.TRACON : N90.TRACONControlling Facilities.Tower : JFK.TowerOperator.Common Carrier : Air CarrierMake Model : B757 Undifferentiated or Other ModelMission : PassengerFlight Phase.Descent : ApproachAircraft / 2Controlling Facilities.TRACON : N90.TRACONControlling Facilities.Tower : JFK.TowerOperator.Common Carrier : Air CarrierMake Model : B747 Undifferentiated or Other ModelFlight Phase.Descent : ApproachPerson / 1Function.Oversight : PICFunction.Flight Crew : CaptainASRS Report : 558222Person / 2Function.Flight Crew : First OfficerPerson / 4Function.Controller : ApproachPerson / 3Function.Oversight : PICFunction.Flight Crew : CaptainPerson / 5Function.Controller : LocalEventsAnomaly.Non Adherence : ClearanceAnomaly.Non Adherence : Published ProcedureIndependent Detector.Other.Flight CrewA : 1Resolutory Action.Flight Crew : Took Precautionary Avoidance ActionResolutory Action.Controller : Issued AdvisoryResolutory Action.Controller : Issued New ClearanceSupplementaryProblem Areas : Airspace StructureProblem Areas : ATC Human PerformanceProblem Areas : Environmental FactorProblem Areas : Flight Crew Human PerformancePage 78Narrative :WE SUSPECTED THAT WE WERE FOLLOWING A B747 COMING INTO JFK AS WE WERE BEING VECTOREDFOR THE VOR RWY 13L APCH. WE SUSPECTED THIS BECAUSE OF THE CALL SIGN OF THE ACFT WHICHUSUALLY FLIES B747'S INTO JFK. NOTICING ON THE TCASII THAT THIS ACFT WAS LESS THAN 10 MI AHEADOF US, AND WE WERE GAINING ON HIM, I ASKED ATC WHAT KIND OF ACFT WE WERE FOLLOWING. HEHEMMED AND HAWED A BIT, AND FINALLY SAID THAT WE WERE NOT FOLLOWING ANYONE. THIS DID NOTFIT WITH WHAT WE WERE SEEING ON THE TCASII AND WHAT WE WERE HEARING ON THE RADIO. OFCOURSE, SINCE ATC WOULD NOT ACKNOWLEDGED THAT WE WERE INDEED FOLLOWING A B747, HE DIDNOT GIVE A WAKE TURB WARNING EITHER. LATER IN THE APCH, WHEN WE SWITCHED TO TWR FREQ, THETWR CTLR IMMEDIATELY INFORMED US -- WITHOUT ANY QUERY OR PROMPTING FROM US -- THAT WEWERE BEHIND A B747, ISSUED A CAUTION WAKE TURB, AND TOLD US TO LAND ON RWY 13R TO KEEP USAWAY FROM HIM. I WAS VERY ANGRY THAT THE APCH CTLR HAD ESSENTIALLY LIED TO US ABOUT THEB747 AHEAD OF US, AND DIDN'T BOTHER TO WARN US ABOUT WAKE TURB EITHER. I GOT THE IMPRESSIONTHAT THE REASON HE DID NOT WANT US TO KNOW WHAT WE WERE FOLLOWING IS BECAUSE HE DIDN'TWANT US TO SLOW DOWN ANY MORE. HE HAD JUST PREVIOUSLY TOLD US TO NOT SLOW ANY MOREUNTIL CRI. HE WAS MORE CONCERNED ABOUT KEEPING HIS TFC MOVING ACCORDING TO HIS PLAN THANFOR THE SAFETY OF OUR AIRPLANE. I WOULD THINK THAT AFTER WHAT HAPPENED WITH A RECENT ACRWAKE TURB INCIDENT, CTLRS WOULD HAVE A BIT MORE RESPECT AND CONCERN FOR JUST HOWSERIOUS WAKE TURB CAN BE, BUT SADLY THAT DOES NOT SEEM TO BE THE CASE. CALLBACKCONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT SHE RECOGNIZEDTHE CALL SIGN OF THE JET IN FRONT, AND KNEW IT WAS A B747. SHE THEN ASKED THE CTLR FOR 10 MISPACING BEHIND THE B747, AND BEGAN A SPD RESTR BACK TO 180 KTS. THE RPTR STATED THAT THISWAS THE POINT IN WHICH THE APCH CTLR'S COMPLAINT WITH THE FLC BEGAN. THE RPTR STATED THATSHE ALWAYS ASKS FOR MORE THAN 'MINIMUM' SPACING, DEPENDING ON WHAT ACFT TYPE SHE ISFOLLOWING.Synopsis :B757 FLC CHALLENGE N90 HVY JET SPACING WHEN FOLLOWING A B747 INTO JFK.

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It would be interesting to see if passeur could go back this far.http://www.faa.gov/ATPubs/ATC/Chp5/atc0505.htmlWAKE TURBULENCE APPLICATION e. Separate aircraft operating directly behind, or directly behind and less than 1,000 feet below, or following an aircraft conducting an instrument approach by: NOTE-Consider parallel runways less than 2,500 feet apart as a single runway because of the possible effects of wake turbulence. 1. Heavy behind heavy- 4 miles. 2. Large/heavy behind B757- 4 miles. 3. Small behind B757- 5 miles. 4. Small/large behind heavy - 5 miles. g. TERMINAL. 2.5 nautical miles (NM) separation is authorized between aircraft established on the final approach course within 10 NM of the landing runway when operating in single sensor slant range mode and aircraft remains within 40 miles of the antenna and: 1. The leading aircraft's weight class is the same or less than the trailing aircraft; 2. Heavy aircraft and the Boeing 757 are permitted to participate in the separation reduction as the trailing aircraft only; 3. An average runway occupancy time of 50 seconds or less is documented; 4. CTRDs are operational and used for quick glance references; REFERENCE-FAAO 7110.65, Use of Tower Radar Displays, Para 3-1-9. 5. Turnoff points are visible from the control tower. =======So if I read this correctly, it can be 5 miles to start and get down to 2.5 miles when within 10 miles of the airport.If everyone wanted 10 miles in trail behind a heavy, they (ATC) would never land the number of planes that are placed into the system and there would be delays. There's an instance where 10 miles is applied in section 5-5-1. 5-5-4 allows much closer with different equipment than 5-5-1.Note the above assumes n90 is using the Broadband Radar System or Full Digital Terminal Radar System.