PHL CTLR EXPRESSED CONCERN REGARDING WAKE TURB EVENT AND INTERSECTING RWY OPS.
Synopsis
PHL CTLR EXPRESSED CONCERN REGARDING WAKE TURB EVENT AND INTERSECTING RWY OPS.
Narrative
I WAS WORKING LCL CTL ON A RWY 9 AND RWY 17 OP. I WAS WORKING THE LCL CTL E POS. MY PRIMARY RESPONSIBILITIES ARE TO GET THE DEPS OFF OF RWY 9L WITH ARRS LNDG RWY 17. RWY 9L AND RWY 17 CROSS; SO TIMING IS VERY IMPORTANT! MOST OF MY DEPS OFF OF RWY 9L WERE 2 MI INCREASING TO 3 MI. I HAD AN AIRBUS DEPART OFF RWY 9L AND MY NEXT ACFT FOR DEP WAS AN MD80. I GAVE ACFT X A TKOF CLRNC WHEN THE AIRBUS WAS 2 MI AHEAD. WHEN ACFT X WAS ABOUT 1 1/2 MI OFF THE DEP END THE SUPVR IN CHARGE MADE A STATEMENT LIKE 'OH MY GOD.' WHEN I LOOKED OUT THE WINDOW THE MD80 WAS IN A SEVERE 'R BANK' AND THEN OVER-CORRECTED TO A L BANK AND THEN STRAIGHTENED OUT. IT SEEMED TO 'SHIMMY' FOR THE NEXT 1/2 MI AND THEN LOOKED NORMAL. ACFT X THEN ASKED ME WHAT TYPE ACFT DEPARTED IN FRONT OF THEM BECAUSE THEY EXPERIENCED WAKE TURB. THE WIND WAS AROUND 110 DEGS AT 5 KTS. I CAN'T REMEMBER SEEING ANYTHING LIKE THAT IN THE 13 YRS AT PHL. MANY CTLRS WITNESSED THIS INCIDENT AND I BELIEVE IT WAS DOCUMENTED AT OUR FACILITY. HOWEVER; THIS IS NOT WHY I AM WRITING ABOUT THIS SIT. A RWY 9 AND RWY 17 OP IS VERY STRESSFUL AND COMPLICATED. THERE IS A LOT OF COORD INVOLVED IN THIS OP. GND CTL AND LCL W ASK FOR RWY XINGS. RWY 9R ARRS MUST CROSS THE DEP RWY 9L. GND CTL ASKS FOR XINGS ON RWY 17 TO REACH RWY 8 WITH PROP DEPS. LCL E TYPICALLY GIVES THE RWY 9L DEP SEQUENCE TO ALL THE DEPS. THE MOST STRESSFUL FUNCTION IS TO GET THE DEPS OFF RWY 9L IN BTWN THE RWY 17 ARRS. THE TRACON TRIES TO GIVE A 7 MI GAP ON RWY 17 ARRS. SOMETIMES YOU ONLY GET A 3-4 MI GAP. SO AS A LCL E CTLR; I WILL TRY TO GET AS MANY DEPS OFF RWY 9L BEFORE THE RWY 17 ARR REACHES THE THRESHOLD. WHEN A DH8 LANDS RWY 17; MOST EXIT AT TXWY K AND SOME USE TXWY H; FEW WILL USE TXWY G. I HAVE NEVER SEEN A DH8 ROLL THROUGH THE INTXN. THERE IS A LOT OF TIME BTWN A 1/2 MI FINAL AND WHEN THEY EXIT ONTO TXWY K. THIS TENDS TO BACK UP THE RWY 9L DEPS AND WE GET A LOT OF DELAYS ON THIS RWY OP. MY SOLUTION IS TO ALLOW THE DH8'S TO HOLD SHORT OF RWY 9L. THIS WAS ALLOWED IN THE PAST. IT WOULD ALLOW FOR A SMOOTH OP WITHOUT A LOSS OF SAFETY. IT WOULD REDUCE DELAYS. IT WOULD ALLOW A CTLR NOT TO FEEL AS THEY NEED TO 'PUMP' THE ACFT OFF RWY 9L. I DON'T KNOW THE RAMIFICATIONS OF TRYING TO CHANGE THIS RULE. IT MAY BE 'MOOT' ANYWAY WITH THE RJ'S TAKING OVER THE PROP'S RTES. HOWEVER MY LINE OF THOUGHT IS LOGICAL. SUPPLEMENTAL INFO FROM ACN 610493: ON TKOF; WE ENCOUNTERED THE WAKE VORTEX OF A PRECEDING AIRBUS 319 AT 400 FT AGL. OUR ACFT BEGAN AN UNCOMMANDED ROLL TO THE R. I APPLIED AILERON AND RUDDER TO COUNTERACT THE ROLL; BUT WAS UNABLE TO STOP THE ROLLING TENDENCY UNTIL WE HAD REACHED APPROX 45 DEGS OF R BANK. AT THIS POINT I HAD NEARLY FULL OPPOSITE RUDDER AND AILERON APPLIED. WE RECOVERED TO WINGS LEVEL BRIEFLY BEFORE THE ACFT BEGAN TO ROLL L. THIS WAS A MINOR ROLL TO ABOUT 15 DEGS OF BANK. IT WAS FOLLOWED BY ANOTHER R ROLL TO ABOUT 25 DEGS OF BANK. ALL ROLLING MOMENTS WERE VERY SMOOTH WITH NO TURB ENCOUNTERED. THE ACFT REMAINED IN TKOF CONFIGN (THE LNDG GEAR WAS UP); FLAPS EXTENDED 11 DEGS AND TKOF PWR THROUGHOUT THE EVENT. THE ACFT CONTINUED TO CLB IN SPITE OF THE ROLLING TENDENCIES; SO I DID NOT ADD ANY ADDITIONAL PWR. WHEN THE RECOVERY WAS COMPLETE; THE FO MADE A PIREP TO PHL TWR ABOUT THE EVENT. TWR COMMENTED THAT THEY HAD OBSERVED THE EVENT AND CONFIRMED THAT WE WERE FOLLOWING AN A319.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.