Separate 737 Max engine anti-ice system issue prompts FAA action

The FAA has taken action to address another issue involving the anti-ice system on Boeing’s 737 Max, after Boeing notified the regulator that a fault could render the system inoperative. Details of the latest anti-ice system concern come as Boeing works to fix for a separate and unrelated anti-ice problem that generated controversy in recent months. In a new proposed order, the FAA says the anti-ice system on 205 US-registered 737 Max jets can possibly become inoperative if the standby power system control unit fails. The regulator has known about the issue for some time. Boeing identified the problem in 2021 during a review of flight deck systems, and notified the FAA about the concern that same year. In November 2022, Boeing issued a bulletin to operators specifying a technical fix. ”Boeing fully supports the proposed directive, which makes mandatory the instructions we shared with operators in November 2022. We continue to provide our customers the support they need to address this issue,” Boeing tells FlightGlobal. “This is not an immediate safety of flight issue and the fleet can continue operating safely.” The FAA’s proposed order says “a potential single point of failure exists” in the 737 Max’s standby power system control unit. Such a failure can result in a “non-latent loss of the entire battery bus and consequent unannunciated loss of control and indication of both engine anti-ice systems”, adds the document, posted to the US government’s regulatory notice database on 14 February. It adds that the condition, if not addressed, could result in loss of thrust on both engines due to damage from operation in icing conditions without the anti-ice system activated. The FAA says its action responds to “a Boeing review” of the 737 Max’s standby power system control unit. The agency did not immediately respond to a request for comment.<br/>