Narrative:

We approached den for a night landing and were told to expect the visual. We were not able to see the airport in spite of a vector by ATC. We had the localizer tuned and identified and were prepared to track it inbound. ATC told us that we could not do this without the airport in sight and we were issued an 'immediate' left turn. We were vectored around for an ILS. However; the 'missed visual' significantly increased our workload. As we intercepted the localizer; we were told that we were close in trail of a 737 and were issued the standard wake turbulence warning. We were also told to maintain 170 knots to the FAF. As we began our descent on the glideslope; we began to 'feel' what we perceived to be edges of the wake turbulence from the preceding aircraft. We discussed and agreed to fly the glideslope one dot high. It is my belief that in reconfiguring the descent to fly this glideslope slightly high; we began to slow. According to the post landing phone call with ATC; we started slowing approximately 2 miles prior to the FAF. Both crew members should be in stated agreement before accepting a visual approach. We should have asked for the ILS upon initial contact and once 'lined up' converted it to a visual. I believe that had we asked for an ILS to begin with; we would not have had the increased workload and would have been able to manage the aircraft more precisely. If airspeed changes are required due to wake turbulence avoidance; ATC should be notified. Contributing to this situation was an early switch to tower and we were on tower frequency when the slowing apparently began...therefore; there was no opportunity for direct communications with ATC. In the future; as part of my approach briefing; I will be including this 'visual approach' guidance.

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Original NASA ASRS Text

Title: Citation First Officer reported an airspeed deviation occurred on approach into DEN in an attempt to mitigate possible wake turbulence.

Narrative: We approached DEN for a night landing and were told to expect the visual. We were not able to see the airport in spite of a vector by ATC. We had the localizer tuned and identified and were prepared to track it inbound. ATC told us that we could not do this without the airport in sight and we were issued an 'immediate' left turn. We were vectored around for an ILS. However; the 'missed visual' significantly increased our workload. As we intercepted the localizer; we were told that we were close in trail of a 737 and were issued the standard Wake Turbulence warning. We were also told to maintain 170 knots to the FAF. As we began our descent on the glideslope; we began to 'feel' what we perceived to be edges of the wake turbulence from the preceding aircraft. We discussed and agreed to fly the glideslope one dot high. It is my belief that in reconfiguring the descent to fly this glideslope slightly high; we began to slow. According to the post landing phone call with ATC; we started slowing approximately 2 miles prior to the FAF. Both crew members should be in stated agreement before accepting a visual approach. We should have asked for the ILS upon initial contact and once 'lined up' converted it to a visual. I believe that had we asked for an ILS to begin with; we would not have had the increased workload and would have been able to manage the aircraft more precisely. If airspeed changes are required due to wake turbulence avoidance; ATC should be notified. Contributing to this situation was an early switch to Tower and we were on Tower frequency when the slowing apparently began...therefore; there was no opportunity for direct communications with ATC. In the future; as part of my approach briefing; I will be including this 'visual approach' guidance.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.