PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Air Traffic Control Military 2; Flight Crew Last 90 Days 120; Flight Crew Total 10300; Flight Crew Type 2000
Situational Awareness
Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert
Weather
Filed IFR for an instrument training flight. During weather briefing no reports of icing or potential icing were seen on 1800wxbrief.com. Departed from ZZZ in VMC conditions; but entered IMC at cruising altitude of 4;000 feet MSL. Temperature at 4;000 feet was +2 degrees C. The winds aloft; checked via ADDS (Aviation Digital Data Service); had forecast +2 degrees C up to 6;000 feet. Descending into destination airport (CXY) started picking up ice after descending through 3;000 feet while being vectored for the ILS approach to Runway 8 at CXY. Despite defrost being set at max; the windshield iced over. Approaching minimums I was focused on trying to sight the runway and approach lights and my student diverted his attention from the ILS display to the windshield as well; resulting in a low altitude alert from the Control Tower. While descending through 1;000 feet MSL the ice began melting. Surface temperature was +1 degrees C. As there was an apparent temperature inversion; decided to check latest weather via ADDS and saw that temperature at CXY and at planned [cruising] altitude (5;000 feet MSL) was positive. Conducted return flight to ZZZ and briefly picked up light icing while climbing through 2;000-3;000 feet. At cruise altitude OAT showed +2 degrees and there was no icing for the return flight beyond the climb-out phase.
PA-28 flight instructor reported encountering unexpected icing during IFR training flight.