Flight crew reported that during takeoff they dialed in an incorrect frequency while trying to conta...

Narrative:

Upon takeoff on xxr at ZZZ; we were flying the zzzzz's 3 departure procedure. Usually tower promptly switches us to departure but there was a delay and the pm queried the tower controller for a switch. Tower did not immediately respond; roughly 10 seconds later tower issues us a change to a departure frequency that was not what was in our clearance. The pm switched to that frequency but it turned out to be a local tower; we then immediately switched to what was issued in our clearance which turned out to be the correct one. Approach asked us why it took so long for us to switch and that they were looking for us on guard as well. Nothing else was asked and the flight continued uneventfully.the ZZZ controller was working both tower and ground at the time of our departure and it was moderately busy. I think controller became confused and issued us the wrong frequency. I assumed it was a last minute change by approach.make sure local towers have 2 controllers on duty to split up tower and ground frequencies. The return of air traffic is happening quicker than the FAA realizes and they need to staff accordingly. We should have asked controller to confirm the new frequency but the tower frequency was quickly becoming congested and hard to get a word in without delaying our switch to approach even longer.

Original NASA ASRS Text

Title: Flight crew reported that during takeoff they dialed in an incorrect frequency while trying to contact Departure. The crew attributed the error in part; to the Tower Controller working both Local and Ground positions.

Narrative: Upon takeoff on XXR at ZZZ; we were flying the ZZZZZ's 3 departure procedure. Usually Tower promptly switches us to Departure but there was a delay and the PM queried the Tower Controller for a switch. Tower did not immediately respond; roughly 10 seconds later Tower issues us a change to a departure frequency that was not what was in our clearance. The PM switched to that frequency but it turned out to be a Local Tower; we then immediately switched to what was issued in our clearance which turned out to be the correct one. Approach asked us why it took so long for us to switch and that they were looking for us on guard as well. Nothing else was asked and the flight continued uneventfully.The ZZZ Controller was working both Tower and Ground at the time of our departure and it was moderately busy. I think Controller became confused and issued us the wrong frequency. I assumed it was a last minute change by Approach.Make sure local towers have 2 controllers on duty to split up Tower and Ground frequencies. The return of air traffic is happening quicker than the FAA realizes and they need to staff accordingly. We should have asked Controller to confirm the new frequency but the Tower frequency was quickly becoming congested and hard to get a word in without delaying our switch to Approach even longer.

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.

Attributes
ACN	1747988
Time
Date	202006
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Tower
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Flight crew reported that during takeoff they dialed in an incorrect frequency while trying to contact departure. The crew attributed the error in part; to the tower controller working both local and ground positions.