Although the Federal Aviation Administration (FAA) is requiring all turbojet operators to land with a 15 percent safety margin by Sept. 1, it will still partly be up to operators to determine when an additional landing safety assessment is needed.
The extra 15 percent margin applies to the additional runway length needed beyond the actual landing distance required by the aircraft type, also in accordance with its weight, capabilities and deceleration systems. The margin also must be based on exact runway conditions, as well as meteorological and other factors expected at time of arrival.
Existing FAA regulations simply state that operators must abort or curtail their operations when conditions are “hazardous,” and only under these circumstances must there be a before-takeoff determination of landing distance using the 15 percent safety margin.
As FAA puts it: “Although an airplane can be legally dispatched under these conditions, compliance with these requirements alone does not ensure that the airplane can land safely within the distance available on the runway actually used for landing in the conditions that exist at the time of arrival, particularly if the runway, runway surface condition, meteorological conditions, airplane configuration, airplane weight, or use of airplane ground deceleration devices is different than that used in the preflight calculation.”
However, FAA adds that this assessment doesn’t necessarily translate into a specific calculation before every landing. “In many cases, the before-takeoff criteria, with their large safety margins, will be adequate to ensure that there is sufficient landing distance with at least a 15 percent safety margin at the time of arrival,” the agency states.
Furthermore, only when the conditions at the destination airport deteriorate while en route, or when the takeoff is conducted under parts 121 or 135, would such an assessment be needed.
Not requiring an extra assessment for every landing makes sense to aviation safety consultant Gunnar Kuepper, chief of operations with Emergency and Disaster Management, Inc., Los Angeles. Otherwise, unnecessary additional cost burdens would be placed on operators.
FAA says the assessments could be the responsibility of flight crews, or done through some other means that the agency does not describe yet in detail, so long as the procedures “account for all factors upon which the preflight planning was based and the actual conditions existing at time of arrival.” It also is likely that operators will have to ensure that their procedures produce results that are at least as conservative as those stipulated by manufacturers.
On June 7, FAA published an “advance notice” of its new landing-distance policy, which was inspired by the December 2005 Southwest Airlines runway overrun at Chicago Midway Airport (MDW). Although it’s not a proposed rulemaking with a public comment period, FAA still indicates that certain provisions mentioned in the June 7 notice are tentative (FAA’s notice can be found at http://www.aviationtoday.com; click on “Daily News Archive” and then “June 7, 2006.”)
At any rate, FAA will be firming up the policy and presenting it in more detail no later than June 30 through a document known as OpSpec/MSpec C082, “Landing Performance Assessments After Dispatch.” After that, operators will have to submit their proposed compliance procedures by Sept. 1. Finally, a month after that, on Oct. 1, they will have to actually be in compliance.
The June 7 notice arrived just a couple of weeks before the National Transportation Safety Board‘s two-day public hearing scheduled for June 20-21 on the Southwest accident and the issue of landing distances.
FAA’s actions are both overdue and welcome, Kuepper says. He adds that there seems to be an increasing number of passenger aircraft accidents that derive from landing performance issues — besides the one involving Southwest. The list also includes last summer’s overrun of an Air France jet at Toronto Pearson Int’l (YYZ).
Strangely enough, the June 7 notice offers no explanation for the logical derivation of the 15 percent figure, but this may be covered in more detail in OpSpec/MSpec C082.
An FAA spokeswoman tells Air Safety Week that there are two basic reasons for adopting the 15 percent figure. First, as already mentioned, the current regulations for calculating the landing distance in hazardous conditions call for the extra 15 percent safety margin. Second, this same margin is a requirement of the European Aviation Safety Agency, so there’s the additional desire to harmonize U.S./European regulations.
While that answer explains where FAA is lifting the figure from, it does not shed light on how the figure was calculated in the first place.
The June 7 notice also offers a sampling of possible compliance methods for operators, which is not intended to be comprehensive. In part, FAA suggests:
- Establishment of a minimum runway length required under the worst case meteorological and runway conditions for operator’s total fleet or fleet type that will provide runway lengths that comply with this notice and OpSpec/MSpec C082.
- Tab or graphical data accounting for the applicable variables provided to the flight crew and/or dispatcher, as appropriate to the operator’s procedures.
- Electronic flight bag equipment that can account for the appropriate variables.
It’s also anticipated that operators will have to do their landing-distance assessments as close to time of landing “as practicable,” given the other tasks the flight crew must complete and information that is available at the time.
Assessments should also be based on the most adverse conditions possible. “For example, if the runway condition is reported as fair to poor, or fair in the middle, but poor at the ends, the runway condition must be assumed to be poor for the assessment of the actual landing distance. This example [also] assumes the entire runway will be used for the landing. If conditions change between the time that the assessment is made and the time of landing, the flight crew must consider whether it would be safer to continue the landing or reassess the landing distance,” FAA says.
Kuepper tells Air Safety Week he is pleased that FAA wants assessments done closer to the time of arrival. Typically, arrival runway assessments have relied on data collected when the runway was certified, not on the runway’s current condition.
There’s an additional issue with landing safety FAA did not address in the June 7 policy notice, Kuepper adds. Accordingly, many pilots have remarked to him that often, when landing in difficult weather conditions, they can’t tell where they are on the runway. If a pilot knows he’s “wasted” at least 1,000 feet of runway by the time he’s touching down, he may want to lift off again and make another go-around.
>>Contact: Jerry Ostronic, FAA, (202) 267-8166; Gunnar Kuepper, (310) 649-0700<<