Legging It

Air Safety Week, Jan 15, 2007

The FAA's Last Word On Extended Range Safety Issues

The FAA published on Jan. 8 the final rule on Extended Operations of Multi-Engined Turbine Powered Airplanes (ETOPS), effective Feb. 15.

The rule was developed from the Nov. 14, 2003 NPRM and applies to air- carrier, commuter and on-demand operators but almost completely excuses compliance by all-cargo carriers with more than two engines. Here's an analysis of the rule and what it means for the industry.

The frequency of long-range flights has grown fourfold since 1984. Last year, airlines scheduled nearly 16,000 flights a week that exceeded 3,000 miles. The 777-200LR has a range of 10,800 miles and Airbus' A340-500 can fly up to 10,300 miles. Legacy carriers are increasingly leaving regional routes to low- cost carriers and are now "in it for the long-haul". Flights over both poles are expected to grow from 1,600 a day to 3,200 a day by 2010.

The new rule is intended to boost dispatch reliability for carriers when alternate airports along a route are unavailable for landing due to inclement weather conditions, FAA air carrier operations branch manager Robert Reich said. A typical ETOPS approval for carriers flying twin-engine aircraft today is 180min, though United Air Lines has one approval for 207min. With the limit opened up, carriers will boost the chances of being able to fly the most efficient routes as the number of alternative airports will be greater.

"The rule has mechanisms for twins to go any length and any duration from an alternate airport, subject to the capabilities of the aircraft," said Reich. The rule brings two-, three- and four-engine aircraft under a common regulation for non-stop operations involving limited diversion airports. According to Reich, the new rule is "intended to eliminate propulsion system reliability as a consideration from the maximum diversion time capability of the airplane. Only the most time-limiting airplane system capability [fire suppression, oxygen, etc.] will determine the maximum diversion time capability for a two-engine airplane under the new requirements."

Reich pointed out that the FAA also extended most requirements previously applicable only to two-engine airplanes to a limited number of part 121 passenger-carrying three- and four-engine airplane operations. However, he added, "the rule excludes the ETOPS maintenance requirements from the operation of airplanes with more than two engines. FAA has sensibly accepted the argument that current engine reliabilities and the level of engine redundancy on such airplanes is sufficient to safeguard such operations."

The bruited terms of LROPS and EROPS have now been dismissed in favor of retaining the familiar ETOPS sobriquet, despite its now enlarged meaning. The cost of compliance with the new 297-page rule is estimated at $12.4 million, in today's dollars, for U.S. airlines over a 16-year period.

As wide-ranging rules go, this is a pittance. However, the longer term influence on airplane and system design will be considerable. The big offset will continue to be the fuel and time saved by twin-engine operators of course, via their more direct routings.

The rule codifies and expands existing FAA policy and route authorizations for all part 121 two-engine airplanes conducting ETOPS beyond certain distances from a suitable airport. It adopts most measures evolved over the past 21 years of ETOPS operations but expands the scope and applicability. The requirements applicable to part 121 passenger-carrying three- and four- engine airplanes will also extend to comparable part 135 operations, but only "twins" need bear the costly compliance with ETOPS strict maintenance requirements.

For existing ETOPS operators, nothing much will change in the short term. In eight year's time, new fuel and oil system design rules will come into play but, in most cases, only for new designs. Existing ETOPS aircraft will mostly be grandfathered to permit unfettered continuity of today's style of operations and to reduce the economic impact of compliance.

In its preamble, the rule describes the development of the existing ETOPS strictures via a number of advisory circulars. These saw the increasingly liberalized operating times from suitable airports at single-engine speed in still air go progressively from 75 mins (1977), 120 mins and 138 mins (1985) to 180 mins (1988).

The latter developments were based on a two-fold approval process: a type design approval of the airplane-engine combination and an operational approval consisting of ETOPS maintenance, flight dispatch regimens, and specialist crew training. The preoccupation was then almost solely with engine reliability.

Ultimately, in March of 2000, the industry agitated for (and the FAA issued) "207-minute ETOPS Approval Criteria". That document provided a 15 percent increase in the 180-minute maximum diversion time. However, this approval was limited to ETOPS operators flying in the North Pacific and only applied when weather or airport conditions did not permit normal 180-minute ETOPS flights.