Embraer Jet Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
While on final to RWY 1R we were following an A350 for 1R.  We elected to remain 1/2 dot - 1 dot above glideslope as the winds aloft and at surface were relatively calm with slightly quartering tailwind.  As we descended below 100 feet AGL we experienced the tell tale signs of wake turbulence.  Luckily the aircraft did not experience any violent pitch or roll oscillations.  A missed approach was executed and we immediately cleared the wake vortices.  We were given vectors for another visual to RWY 1R.  On the second approach we had momentary wake turbulence at 2000 feet MSL following an A320.  As stated earlier the wind conditions being calm at all altitudes were prime for wake turbulence. The main purpose of this report is to draw attention to hazards of wake turbulence.  While we all appreciate efficiency of the national airspace system; lots of separation I feel is the key to preventing these occurrences.  We had noticed the aircraft ahead of us was left and right of centerline on approach and feel there may have been glideslope deviations as well.  This very well may have caused staying high on the glideslope on our part to [be of] no benefit if they were high as well.
While receiving vectors for the visual approach to RWY 1R we were told to follow a heavy A350. The controller notified us we were 3 1/2 miles in trail and to caution for wake turbulence. The Captain (pilot flying) told me he would stay above the glideslope to avoid the wake turbulence. We remained 1/2 dot to 1 dot above the glideslope for the entire approach with no signs of turbulence. As we descended below 100 feet AGL we experienced two rolling moments to the left; both of which were corrected by the Captain. These oscillations were not extreme; but were clearly due to the wake turbulence. As these occurred the Captain called and executed a go around; immediately exiting the heavy aircraft's vortices. We were then vectored around for a second visual approach to RWY 1R; this time following an A320. During the approach a light quartering tailwind was reported. We once again remained slightly above glideslope and only experienced minor turbulence on the approach. This situation would have been avoided with increased separation from a heavy aircraft. The efficiency gained from using minimal separation on landing aircraft does not outweigh the risks of wake turbulence. Even by remaining high on the glideslope we experienced an uncommanded roll at a low altitude.
EMB flight crew reported two wake turbulence encounters on successive approaches to IAD.