Narrative:

During an evening flight from phx to den, ZDV told us to 'cross larks at 17000 ft, inbound at 250 KTS.' the phraseology was nonstandard, but since on the larks arrival, it tells you to expect larks at 250 KTS and 17000 ft, we assumed that is what he meant. A few mins later, the controller asked our speed. When we told him 300 KTS, his response was 'I told you 250 KTS, I need you to slow down now or I'm going to give you a big fat left turn.' well, we slowed to 250 KTS almost immediately, and no turn was required (so no loss of separation). He should have given the initial instruction as 'reduce speed to 250 KTS, then cross larks at 17000 ft.' for our part, since his phraseology was nonstandard, we should have had him clarify his statement.

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Original NASA ASRS Text

Title: AN MLG ACFT DSNDING ON THE LARKS 3 ARR MISUNDERSTANDS THE DSCNT CLRNC AND FLIES AT TOO HIGH OF A SPD.

Narrative: DURING AN EVENING FLT FROM PHX TO DEN, ZDV TOLD US TO 'CROSS LARKS AT 17000 FT, INBOUND AT 250 KTS.' THE PHRASEOLOGY WAS NONSTANDARD, BUT SINCE ON THE LARKS ARR, IT TELLS YOU TO EXPECT LARKS AT 250 KTS AND 17000 FT, WE ASSUMED THAT IS WHAT HE MEANT. A FEW MINS LATER, THE CTLR ASKED OUR SPD. WHEN WE TOLD HIM 300 KTS, HIS RESPONSE WAS 'I TOLD YOU 250 KTS, I NEED YOU TO SLOW DOWN NOW OR I'M GOING TO GIVE YOU A BIG FAT L TURN.' WELL, WE SLOWED TO 250 KTS ALMOST IMMEDIATELY, AND NO TURN WAS REQUIRED (SO NO LOSS OF SEPARATION). HE SHOULD HAVE GIVEN THE INITIAL INSTRUCTION AS 'REDUCE SPD TO 250 KTS, THEN CROSS LARKS AT 17000 FT.' FOR OUR PART, SINCE HIS PHRASEOLOGY WAS NONSTANDARD, WE SHOULD HAVE HAD HIM CLARIFY HIS STATEMENT.

Data retrieved from NASA's ASRS site as of July 2007 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.