Suburban heat turbulence today

[Stuart Midgley]

Arriving in Sydney at about 1200 today from Launceston on a Virgin 738, we tracked north over south-western Sydney parallel to the Blue Mountains before turning to the right over Parramatta(ish) and lining up to arrive on the 'main' north-south runway facing south (is that 16R?).

Anyway, as soon as we got over the suburbs proper, out around Campbeltown, it suddenly got lumpy and the lower we got the lumpier it got! On final approach the lurching drops were enough to have many of the passengers exclaiming. I felt/heard the pilot give it a burst of throttle at least once, I think to maintain altitude - probably only a mile or so from the threshold.

I take this sort of turbulence is common in city areas, with all that tar and tile and concrete to heat up under a strong sun? Was anyone flying today & found it particularly bad, or is just that I usually leave/arrive early in the morning and so haven't experienced it before?

Cheers!

[SloppyJoe]

It is possible to get thermals from cities but unlikely to effect a 737 to the point of people making comments. Have just looked at the weather at your time of arrival and wind was gusting from 20-30kts. This is what caused the turbulence you felt. The adding of power is more to maintain airspeed rather than altitude, obviously if you get too slow you will be unable to maintain altitude but the initial response of adding power will always be to maintain airspeed if it is a short momentary burst of power.

Thermals are more noticeable on calm hot days, I assume as stronger winds diffuse the thermal activity.