The recent experience of the crew of a Part 121-operated Embraer ERJ-145 underscores the value of returning to the destination in the event of encountering icing. The crew noticed that ice (which they later classified as “severe”) had begun accumulating on the windshield wipers and nose and that the aircraft’s anti-ice system could not be turned on. As they attempted to operate the anti-ice manually, the system came to life but produced a master warning on the Eicas followed by a “bleed air 2 overtemp” warning.
The flying pilot leveled at FL250 and called for the checklist, which included turning off “bleed air two.” The flying pilot then tried activating “bleed air one,” which quickly produced an “overheat” warning. While still in icing conditions, the crew also received a “wing anti-ice fail” warning.
The pilot declared an emergency and immediately requested a lower altitude to escape the ice. The flight was cleared down to 14,000 feet and then to 10,000 feet. During descent, the “engine 1 anti-ice fail” warning illuminated. For the remainder of the flight and once clear of icing, the flying pilot reengaged the bleeds and no warning messages appeared.
Although the crew had successfully run the “A-ice test” on the ground before departure, as well as the “B-ice test” in the air, they decided to return to their departure airport where the operator’s maintenance staff could look at the problem.
They located a faulty number-two bleed valve as the cause of the incident.