The FAA on Monday will propose a new rule that would require airlines operating aircraft with maximum take off weight (MTOW) of less than 60,000lb (27,216kg) to begin using equipment and or procedures on those aircraft to aid in ice detection during certain portions of flight.
Prompted initially by the ice-related fatal crash of an American Eagle ATR 72 near Roselawn, Indiana in 1994, the notice of proposed rulemaking (NPRM) represents the FAA's attempt to address lingering concerns about flight in icing conditions, particularly for smaller commuter-type aircraft, and how pilots operate ice prevention equipment.
The FAA until now has been addressing potential issues on a per-aircraft basis through dozens of airworthiness directives (ADs). Those mandates were based in part on the findings of an aviation rulemaking advisory committee (ARAC) launched in 1997 to investigate the need for ice detectors or other means for alerting crews to active de-ice or anti-icing systems to remove or prevent to the accumulation of ice on critical aircraft surfaces.
"An evaluation of accidents and incidents led to the conclusion that the ADs do not provide adequate assurance that the flight crew will be made aware of when to activate the airframe ice protection system (IPS)," the FAA says.
FAA says a "limited analysis" of past icing events revealed that aircraft above the 60,000lb cut-off have not "experienced accidents due to in-flight icing, while airplanes with lower certified MTOWs have an event history".
The agency notes, however, that if the limit were raised to 66,000lb, the new rule would encompass the Bombardier Q400, which was involved in a fatal accident near Buffalo, New York this February. Icing was originally thought to be a factor in the actions that led to the Colgan Air aircraft to crash, though US National Transportation Safety Board (NTSB) investigators have downplayed the role of icing as the investigation has proceeded.
The new NPRM would require crews to activate icing protection systems based on one of three airframe icing cues: a primary (redundant) airframe ice detection system; an advisory (non-redundant) detector coupled with visual cues; and a method of using temperature and visible moisture conditions as a threshold to active the IPS during most non-cruise flight phases.
FAA in parallel with the NPRM has released a draft advisory circular to help operators determine how to satisfy the new requirements, which it says will cost $5.5 million during the next 20 years. Offsetting the expense would be savings of $17.3 million by eliminating one accident and four fatalities.
The new rules would also satisfy NTSB recommendations that came in the wake of the fatal crash of a Cessna Citation 560 business jet on approach to Pueblo, Colorado in 2005, says the FAA.
Certain recommendations from the ARAC continue to be evaluated by the FAA, including a measure to require "certain" Part 121 aircraft to exit icing conditions. The FAA had earlier mandated the advanced ice detection methods for new build aircraft.
Source: Air Transport Intelligence news
