Federal Aviation Administration Seeks New Safeguards on Boeing 737s: Proposal Would Mandate Changes Designed to Ensure Adequate Flight Speeds

The Wall Street Journal

By Andy Pasztor

March 2, 2014 7:32 p.m. ET


U.S. aviation regulators want cockpit-automation fixes on nearly 500 Boeing Co. 737 planes, seeking to prevent pilot errors that over the years have caused fatal crashes of several jet and turboprop airliners.

The Federal Aviation Administration's proposed safety directive, which will be formally released for public comment on Monday, aims to ensure that all pilots of 737-600 models and later versions have adequate safeguards if airspeed drops dangerously low, particularly during landing approaches.

Foreign regulators are expected to follow the FAA's lead in demanding changes to parts of the aircraft's flight-control computers, likely affecting an additional 700 or more of the widely used 737s.

Chicago-based Boeing previously recommended the changes, but the FAA wants to make them mandatory.

The latest move comes amid an escalating industrywide debate over the most-effective cockpit designs to warn pilots if automated throttle systems aren't properly engaged or suddenly turn off, resulting in planes flying too slowly on approach.

Such problems with low airspeed—often prompted by confusion about the status of automated throttles—have been identified as major factors in some of the most infamous airliner crashes in recent years. They include last summer's crash of an Asiana Airlines Boeing 777 into a sea wall while trying to land at San Francisco International Airport. The pilots failed to notice their approach speed dropping.

In 2009, a Colgan Air turboprop crashed near Buffalo, N.Y., killing all 49 people aboard, after pilots allowed airspeed to decay. The accident shined a spotlight on the shortcomings of regional airlines.

Specifically, the FAA's proposal stems from the Feb. 25, 2009 crash of a Turkish Airlines Boeing 737, which went down short of an Amsterdam runway, after a faulty altimeter caused the plane's automated throttle system to prematurely roll back thrust. The crew failed to notice the discrepancy in time; nine people were killed.

In the wake of that accident, Boeing started installing a more-prominent audible warning system—featuring a computer-generated voice—on 737 models rolling out of its factories.

The company also issued a series of nonbinding service bulletins, recommending that thelarge global fleet of previously built 737s be retrofitted with features designed to ensure that autothrottles maintain safe flight.

In its proposal, the FAA said "loss of automatic speed control" can result "in loss of control of the airplane." The agency is proposing a three-year compliance deadline, once the directive becomes final.

Over the weekend, a Boeing spokesman said the manufacturer has "received limited reports" of altimeter discrepancies since the Amsterdam accident, but none of those led to accidents.

At the same time, the FAA is working to clarify long-standing policies and safety advisories related to cockpit features for low-speed alert and protection systems. Public comments on those proposals are due within a week.

The agency, however, has stopped short of embracing wide-ranging regulatory changes affecting the certification of new types of airliners, despite prodding by the National Transportation Safety Board, some plaintiff lawyers representing families of air-crash victims and a number of independent air-safety advocates.

For years the NTSB and outside experts have called on the FAA to require more-extensive low-speed alerts, including a computer-generated voice warning that says "low airspeed," to help pilots of airliners and charter aircraft avoid potentially catastrophic aerodynamic stalls near the ground.

The Boeing spokesman said the company has "determined that no design changes are required" beyond those already voluntarily instituted by the company.

In the past, Boeing and FAA officials have generally responded to calls for alerting changes by emphasizing that aircraft already have visual cockpit warning symbols and are equipped with so-called "stick shaker" devices, which vibrate control columns when approaching a stall.

In the wake of the high-profile San Francisco crash, Boeing safety officials said that enhancing the 777's low-speed warning system with a computer-generated voice could have the unintended consequences of distracting pilots in a cockpit that already features an array of visual and audible warnings for different systems.

Source:  http://online.wsj.com