Pilot and backseat pilot reported not exceeding 230 KIAS; but ATC was upset because they showed a gr...

Attributes
ACN	1383900
Time
Date	201608
Local Time Of Day	0601-1200
Place
Locale Reference	PCT.TRACON
State Reference	VA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Military Trainer
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	None
Person 1
Function	Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Instrument
Experience	Air Traffic Control Military 5 Air Traffic Control Radar 20 Flight Crew Last 90 Days 10 Flight Crew Total 2400 Flight Crew Type 250
Person 2
Function	Pilot Not Flying
Qualification	Flight Crew Commercial Flight Crew Instrument
Experience	Flight Crew Last 90 Days 32 Flight Crew Total 2637 Flight Crew Type 3
Events
Anomaly	ATC Issue All Types Deviation - Procedural FAR Deviation - Speed All Types

Narrative:

[I] was on a cross country [flight]; 240 heading; 2;500 feet MSL at 210-230 knots IAS. The garmin 530 waas fluctuated between 255-268 knots groundspeed. Was not concerned as IAS never exceeded 230 knots. Upon landing the ground controller advised me to contact potomac TRACON for a speed violation and provided a phone number. Once contacted potomac TRACON requested personal and pilots certificate information and stated they had me on radar at 262 knots.I checked weather after this call and the winds aloft were 060 17-20 kts and a density altitude of 4;500 feet during my flight at 2;500 feet MSL. I also had my transponder checked. I am very familiar with the washington dca airspace and speed restrictions of which this flight was conducted on the outer periphery of the 230 knots 60 NM mile ring. This is not the first time controllers have asked me to confirm airspeed in this area as they don't factor winds aloft or density altitude. In the past inside the 180 knots 30 mile ring controllers have told me their radar show 30-40 knots higher than my IAS of 170-180 while transiting the dca sfra. What may have triggered potomac TRACON was an unusual northeast-southwest winds aloft plus density altitude giving the controllers a high groundspeed during this flight.

Original NASA ASRS Text

Title: Pilot and backseat pilot reported not exceeding 230 KIAS; but ATC was upset because they showed a ground speed of 262 KTS.

Narrative: [I] was on a cross country [flight]; 240 heading; 2;500 feet MSL at 210-230 knots IAS. The Garmin 530 WAAS fluctuated between 255-268 knots groundspeed. Was not concerned as IAS never exceeded 230 knots. Upon landing the ground controller advised me to contact Potomac TRACON for a speed violation and provided a phone number. Once contacted Potomac TRACON requested personal and pilots certificate information and stated they had me on radar at 262 knots.I checked weather after this call and the winds aloft were 060 17-20 kts and a density altitude of 4;500 feet during my flight at 2;500 feet MSL. I also had my transponder checked. I am very familiar with the Washington DCA airspace and speed restrictions of which this flight was conducted on the outer periphery of the 230 knots 60 NM mile ring. This is not the first time controllers have asked me to confirm airspeed in this area as they don't factor winds aloft or density altitude. In the past inside the 180 knots 30 mile ring controllers have told me their radar show 30-40 knots higher than my IAS of 170-180 while transiting the DCA SFRA. What may have triggered Potomac TRACON was an unusual NE-SW winds aloft plus density altitude giving the controllers a high groundspeed during this flight.

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.