Large Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1
Situational Awareness; Communication Breakdown; Distraction; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented
Airspace Structure; Human Factors; Procedure
PHX was on west flow with a high arrival rate. A large storm from the southeast was rolling in with a dust storm north of it heading towards IWA. I had two IFR inbounds that IWA Tower approved to land opposite direction because the dust storm was now on a 7 mile final. My next two IFR inbounds did not want to attempt the active runway so IWA changed runways. I was making point outs to the finals sectors to go further north than usual because of the dust storm.At the time I got a handoff Aircraft X was issued a 170 heading and 10000 feet. Aircraft X was on vectors in a box holding pattern waiting for pilot to say intentions. IWA now had 1/2 mile visibility. Aircraft X didn't respond to the initial heading and altitude I issued as I moved on to another clearance for a different airplane. Aircraft X came back and asked for a southbound heading for weather. I reissued 170 heading and 10000 feet. I heard the read back and moved on. A few minutes later I realized he was at 8200 feet in the 9800 foot Minimum Vectoring Altitude. I asked Aircraft X for their current altitude and to say assigned altitude and to stop his descent. He responded with 7000 feet as his assigned altitude. After listening to the replay; the pilot was issued 10000 feet and read back 7000 feet. I then climbed him back to 10000 feet and continued holding for a few more minutes until he diverted. The Low Altitude Alert never went off.
P50 Controller vectoring an aircraft in a holding pattern reported an aircraft assigned 10;000 feet read back 7;000 feet and descended to 8;200 feet which was below the Minimum Vectoring Altitude.