AN ACR B727 FREIGHTER FLC HIT THE WAKE OF ANOTHER B727 WHILE PERFORMING A CLOSE-IN NOISE ABATEMENT DEP. THE RPTR FEELS THAT THIS TYPE OF PROC IS UNSAFE TO PERFORM DURING THE MASS DEPS.

Date: 1997-11 · Aircraft: B727-100 · Phase: initial_climb

Anomalies: inflight-event-encounter-other-unknown

Synopsis

AN ACR B727 FREIGHTER FLC HIT THE WAKE OF ANOTHER B727 WHILE PERFORMING A CLOSE-IN NOISE ABATEMENT DEP. THE RPTR FEELS THAT THIS TYPE OF PROC IS UNSAFE TO PERFORM DURING THE MASS DEPS.

Narrative

DEPARTED RWY 27 CLOSELY BEHIND ANOTHER B727. INITIATED CLOSE IN NOISE ABATEMENT PROC (FLAPS 15 DEGS AND REDUCED PWR). ABOUT 1500 FT AGL; FLT ENCOUNTERED WAKE TURB FROM PRECEDING ACFT; FLT ROLLED L THEN HARD R. I MADE RAPID AND RADICAL THRUST AND PITCH CHANGES. ADVANCED THRUST FROM 1.7 EPR TO GAR THRUST AND PITCHED FROM +10 DEGS TO - 10 DEGS. ACFT FLEW THROUGH THE VORTEX. I FEEL THAT THIS UPSET AND RECOVERY MANEUVER POSED A SERIOUS THREAT TO FLT SAFETY. THE HIGH DRAG; LOW THRUST CONFIGN OF THE CLOSE IN NOISE ABATEMENT PROC EXPOSES THE FLT TO UNNECESSARY RISK. I FEEL VERY STRONGLY THAT OUR PROCS SHOULD BE REVIEWED TO IMPROVE THE SAFETY MARGIN GIVEN THE VARYING THREATS OF WAKE TURB; TAILWINDS; ICING; MECHANICAL FAILURES; ETC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS THE CAPT ON A B727-100 FREIGHTER ON A NOISE ABATEMENT DEP FROM CVG. HE SAID THAT HIS COMPANY USES THE NORMAL HUB AND SPOKE TECHNIQUE OF MASS ARRS AND DEPS AND THIS GENERATES A NUMBER OF WAKE ENCOUNTERS WITH THEIR OWN ACFT. THE OP AT THIS ARPT IS MORE SENSITIVE THAN USUAL BECAUSE THE WAKE ENCOUNTERS OCCUR WHILE THE ACFT IS NEAR ITS PERFORMANCE LIMITATIONS AND THERE IS OFTEN LITTLE PERFORMANCE MARGIN FOR AN EFFECTIVE RESPONSE. SINCE THIS EVENT HE HAS DECIDED TO CARRY MORE THAN THE RECOMMENDED PWR TO AID IN HIS RECOVERY WHEN HE AGAIN HITS A WAKE. THE CAPT SAID THAT HE SPOKE TO HIS PRINCIPAL OPS INSPECTOR; BUT HE DID NOT SEEM TO BE ABLE TO CONVINCE THE INSPECTOR OF THE RISK INVOLVED. HE ALSO FILED A RPT WITH HIS UNION.

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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.