Commuter aircraft encounters wake turbulence while executing arrival into ATL.
Synopsis
Commuter aircraft encounters wake turbulence while executing arrival into ATL.
Narrative
Upon arrival into ATL; crew was proceeding along a star using the PPAS profile descent angle and airspeed; at flight idle thrust; and on profile to cross ERLIN at 14000 as cleared by ATC. Prior to crossing ERLIN; ATC assigned speed 300 knots; which required acceleration of about 30 knots and an increase in the descent rate. Crew complied with the new speed clearance and descent profile to comply with the clearance to cross ERLIN at 14000; and aircraft was established on speed and descent profile at approximately 16000 in smooth air. At 15000; aircraft simultaneously entered a sudden left roll estimated to be over 30 degrees bank;and a minor downward pitch and the autopilot disconnected. I assumed control using the yoke and adjusted pitch and bank to straight and level and in transition did encounter another less severe pitch and bank change; and then climbed about 200 feet back into smooth air and did advise ATC of the severe wake and that we were unable to descend at this time. ATC cancelled our crossing restriction; and vectored us off course away from the area of turbulence. From that point flight proceeded without further incident. Shortly after the wake encounter; ATC did point out; and we did see a large airplane ahead; but at a distance that would have appeared to pose little to no chance of threat of wake turbulence.
Second reporter narrative
While flying into ATL; what is believed to be wake turbulence was encountered. We were in smooth air; descending through 15;000' to cross Erlin at 14;000'; as assigned by ATC. Speed was 300 KIAS; as assigned by ATC. A sudden and abrupt roll to the left ensued. The Captain (PF) assumed manual control of the aircraft. A sudden and abrupt roll to the right ensued. I am not sure if this was wake or pilot induced; as I was not at the controls. After the third 'cavalry' chime (indicating auto-pilot was not disconnected by the PF); I silenced the warning using the disconnect switch on my yoke. Rapid conversation between me; ATC; and PF took place. I advised ATC that we had a severe wake encounter and were leveling at 15;000'. PF instructed me to request a '2 degree offset'. Instead; I opted to request a 2 mile offset. Prior to the encounter; the aircraft was on a descent profile to cross Erlin at 14;000'. The PF elected to level at 15;000' so as to not descend into the wake. I advised ATC that we would not make the crossing; and ATC indicated that was fine. ATC assigned a heading. After the heading was assigned; PF resumed descent to 14;000'. Simultaneously; I selected TCAS to 'above' & 'below' to try and determine our proximity to the offending aircraft. The nearest aircraft was about 10 miles ahead; and a few thousand feet lower. We had a right quartering tailwind at the time of the encounter; which I recall was about 25 knots. I then immediately called the cabin to ensure the pax and FA's were OK. I spoke to the aft FA; who informed me they were OK. She reported that the forward FA was seated; and she (the aft FA) happened to be holding onto the handle on the galley wall; and was therefore able to maintain her balance. We resumed the arrival and landed without further incident. After arrival at the gate; I asked both flight attendants if they were still OK; and they reported they were. The aft FA said 'thank you for getting us out of whatever that was'. I asked if they would have been able to maintain their footing had they been in the aisle; and both stated that it would have been very unlikely that they could have maintained their balance.
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.