B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 240; Flight Crew Total 25000; Flight Crew Type 15000
Situational Awareness; Communication Breakdown; Confusion
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Requested ATC Assistance / Clarification
Human Factors; Chart Or Publication; Procedure; Manuals
It was the second time in a row that I have had a problem with ATC terminology while descending via the ALDAN 1 arrival into KRDU; but I will just stick to today's event. When north of SBV we were cleared to descend via the ALDAN 1 arrival with a speed assignment. At some point; Washington Center said 'resume normal speed.' This is an ambiguous clearance...does it mean 'delete speed restrictions' or 'comply with published speeds?'I possess an FAA document titled 'Climb via/Descend via speed clearances faqs' from which I quote the last page...21Q 'The controller had issued a speed for me to maintain. Later; the controller says 'resume normal speed'. Can I fly a speed at my discretion?Answer: Yes; but a controller can only issue that clearance if you are NOT on a published portion of a procedure that contains speed restrictions. If there are published speeds; the correct clearance would be 'delete speed restrictions' or 'resume published speed'We asked for which one of these he wanted. He admonished us for not knowing what normal speeds were. We could not obtain clarification from him as he did not seem to understand the ambiguity. We were transferred to approach control; where we had to ask for clarification. He immediately resolved it by giving us a speed and altitude direct to the outer marker. Problem solved.
B737 Captain reported confusion about their speed assignment due to the Controller using incorrect phraseology.