EMB ERJ 145 ER/LR
Flight Crew Air Transport Pilot (ATP)
Confusion
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Aircraft Aircraft Damaged; General Maintenance Action
Aircraft; Human Factors
I was deadheading in the cabin and seated in the last aft row. At cruise altitude; likely at a flight level; I looked out the window and saw what appeared to be aircraft wing skin cavitation; on the left wing; on the outboard flap upper surface area near the flap out most hinge area. The right wing area looked similar to the left wing but was less severe. This distortion of skin appeared to go back to normal below 10;000'. I informed the Pilot In Command verbally via interphone and directly upon landing. I informed my supervisors via phone call and followed up with a report.Possible fleet wide issue with EMB-145 skin separating in the wings or possible fatigue. Passengers and cabin crew may not have been able to notice this discrepancy. Therefore; it is possible this EMB aircraft and others have not been noticed before.  I have only seen this once before on an EMB-135 aircraft in December 2012; and brought it up then to the company's attention in a report. An Airworthiness Directive (A/D) to inspect the EMB skin; at high altitudes; should be required. Otherwise; the PIC will never know that the aircraft is experiencing this skin condition. Deadheading Pilot. Possible fleet-wide issue with EMB skin separating. Skin separating/damage.
Reporter stated the collapsing or cavitating panel was actually at the left wing trailing edge just forward of the outboard end of the outboard flap. Once they had descended to 10;000 feet; the wing panel had faired out with the wing and remained smooth even with the flaps extended. Flaps are electrically driven only; no back-up standby system and no hydraulic actuators.Reporter stated that Maintenance did check the wing area and trailing edge panels and they all seemed secured without any damage. Maintenance Control noted there were no reports of vibration from previous flight crews operating the same aircraft; so the aircraft was released to service.
While deadheading in the cabin and sitting in the last row of an EMB-145 aircraft; a Captain notices a section of the left wing trailing edge skin cavitating; collapsing at cruise altitude. Skin distortion appeared to go back to normal below 10;000 feet and remained smooth with flaps extended for landing.