Air carrier flight crew reported experiencing miscommunication that led to a low altitude alert.

Attributes
ACN	1714188
Time
Date	201912
Local Time Of Day	0001-0600
Place
Locale Reference	DEN.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance Inflight Event / Encounter CFTT / CFIT

Narrative:

Assigned heading and altitude during arrival; ATC notified us of a low altitude alert as pm (pilot monitoring) and PF (pilot flying) agreed that they were too low and arrested the decent. ATC assigned a new altitude and heading that was immediately complied with via assuming manual control. The flight returned to a safe altitude and completed an uneventful approach and landing. I believe [that] during the read back; the pm transposed heading 170 and 9;000 feet assigned with heading 190 and 7;000 feet assigned. The fcp was selected to heading 190 and 7;000 feet in the altitude window. Better monitoring by the PF could have helped mitigate this transposition. Also when both the PF and pm questioned the apparent low altitude; a more immediate halt of the descent and a query to ATC would have been the most appropriate course of action.

Original NASA ASRS Text

Title: Air carrier flight crew reported experiencing miscommunication that led to a low altitude alert.

Narrative: Assigned heading and altitude during arrival; ATC notified us of a low altitude alert as PM (Pilot Monitoring) and PF (Pilot Flying) agreed that they were too low and arrested the decent. ATC assigned a new altitude and heading that was immediately complied with via assuming manual control. The flight returned to a safe altitude and completed an uneventful approach and landing. I believe [that] during the read back; the PM transposed heading 170 and 9;000 feet assigned with heading 190 and 7;000 feet assigned. The FCP was selected to heading 190 and 7;000 feet in the altitude window. Better monitoring by the PF could have helped mitigate this transposition. Also when both the PF and PM questioned the apparent low altitude; a more immediate halt of the descent and a query to ATC would have been the most appropriate course of action.

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.