#2 -22 ground speed with atc

Heard an sr-22 a week ago or two on the radio flying through detroit airspace.Center asked what type he was as he was indicating 220 knots at 13,000 feet.He said he was a SR-22 number two off the line.Thought i’d let you all know.The controller was impressed.Just didn’t know what kind he was.

ATC radar gives a ground speed read out. If the SR22 was at 13,000 feet I would guess his Indicated Airspeed was about 150-160 kts giving a True Airspeed (Indicated, or really calibrated, airspeed corrected for altitude and temperature) of about 175-180 kts. All it would then take is a 40 kt tailwind (not unusual if February at 13,000 feet if heading eastbound) to give a groundspeed of 220 kts. Unfortunately, had the aircraft been going the other way the groundspeed on the ATC readout would have been closer to 135-140 kts for the same IAS and TAS.

Remember, when we talk speed we must be clear exactly what type of speed we’re talking about and, if it’s anything other than KTAS we need to correct for altitude and temperature and/or winds aloft. Otherwise any comparisons are meaningless.

Jerrold Seckler

Heard an sr-22 a week ago or two on the radio flying through detroit airspace.Center asked what type he was as he was indicating 220 knots at 13,000 feet.He said he was a SR-22 number two off the line.Thought i’d let you all know.The controller was impressed.Just didn’t know what kind he was.

ATC only sees Ground speed. Never TAS.

With this in mind, the 22 could have been in slow flight as the winds aloft were at 140kts.

Just a joke… but not uncommon… ask the guys that fly around the north. Have a great day.

Looking forward my day… #85

Cheers,

Woor

ATC radar gives a ground speed read out. If the SR22 was at 13,000 feet I would guess his Indicated Airspeed was about 150-160 kts giving a True Airspeed (Indicated, or really calibrated, airspeed corrected for altitude and temperature) of about 175-180 kts. All it would then take is a 40 kt tailwind (not unusual if February at 13,000 feet if heading eastbound) to give a groundspeed of 220 kts. Unfortunately, had the aircraft been going the other way the groundspeed on the ATC readout would have been closer to 135-140 kts for the same IAS and TAS.

Remember, when we talk speed we must be clear exactly what type of speed we’re talking about and, if it’s anything other than KTAS we need to correct for altitude and temperature and/or winds aloft. Otherwise any comparisons are meaningless.

Jerrold Seckler

Heard an sr-22 a week ago or two on the radio flying through detroit airspace.Center asked what type he was as he was indicating 220 knots at 13,000 feet.He said he was a SR-22 number two off the line.Thought i’d let you all know.The controller was impressed.Just didn’t know what kind he was.