Page 41 - World Airnews Magazine May 2020 Edition

GENERAL
TECHNICAL
AVIATION

reversals can exceed structural design limits. structures. A prime example of this occurred when a Boeing 747

Also, certification flight tests involve control input in a single axis nearing Anchorage, Alaska, on March 31, 1993, was in the vicinity A SOLUTION FOR

and single direction. Control reversals will amplify the loads on the of strong mountain wave turbulence.

aircraft’s structures. The jumbo experienced a rapid 50-deg. roll to the left followed

The Airbus document “Managing Severe Turbulence” provides by a significant yaw. Then came several pitch and roll oscillations. WORKFORCE TRANSPORT

additional guidance to flight crews of fly-by-wire (FBW) aircraft The severe turbulence created dynamic multi-axis loadings that so

based upon in-depth analysis of severe turbulence events. Airbus exceeded the structural capability of the No. 2 engine pylon that it
engineers discovered that pilots who followed the prescribed separated from the airplane, taking the engine with it.

recommendations for FBW aircraft to keep the autopilot and auto WHAT IS “MULTI-AXIAL” LOADING AND WHY IS IT

throttles engaged were able to minimize the loads on aircraft, as IMPORTANT TO THIS DISCUSSION?

opposed to flight crews who took over manually.
The manufacturer’s Flight Crew Operating Manual recommenda- Its impact on an engine pylon illustrates this phenomenon perfect-

tions are to follow the target speed (which depends on altitude) when ly. Under normal circumstances in flight, the engine is producing n light of the

turbulence is encountered and keep auto throttles engaged except if a significant amount of forward thrust, thus its pylon endures a Ievents, such as

thrust changes become excessive and keep the autopilot on. direct tensile (pulling) force along its primary axis and is designed airlines grounding
accordingly. Now, consider an abrupt rolling input to the aircraft.

Detailed studies found the autopilot, when combined with the Suddenly, in addition to the tensile force from the thrust-produc-

turbulence-induced motions, limits the aircraft to smaller reac- tion, the pylon experiences a sideways shearing force. This places their aircraft and

tions. In contrast, they also found that pilot pitch-down reaction the pylon into a condition of “multi-axial” force . . . tensile stress countries announcing

to an initial updraft will accentuate the pitch-down effect as the in one direction and shear stress in another. The combination of lockdowns meaning

aircraft flies into the downdraft section. stresses acts in a direction that the structural element was not restricted movement,

This increases the negative load factor and increases the risk and designed to withstand originally, and can lead to failure. companies are facing
number of injuries. major lacks of labour.

A severe turbulence encounter may lead to excessive high-speed SUMMARY Agriculture industry in Europe is in needed nies and governments regarding this particu-
lar matter, too.

or low-speed excursions. This will induce autopilot disconnections Due to the risk of reduced structural integrity of an airplane, the of labourers in order to avoid the deficiency of

and activation of the appropriate flight control law in an FBW air- NTSB is concerned about deficiencies in inspection procedures. fruit and vegetables while other industries are For more information and charter flight or-

craft. In the case of a Vmo/Mmo exceedance, a pitch-up would be Implicit in the high-load and inspection formulation was the missing qualified workers to prevent severe ders, please contact KlasJet’s team at sales@

commanded to reduce the excursion. presumption that the specified inspections would be adequate to consequences. klasjet.aero.

If excessive low speed occurs, the alpha protection law would identify and address damage caused by any such event. KlasJet has been receiving a number of KlasJet is a private and business charter

activate and produce a nose-down movement. In order to keep Canadair and Airbus determined their published inspection cri- enquiries regarding charter services for trans- carrier that provides exclusive group flights

the autopilot engaged as long as possible, flight control software teria were inadequate to ensure safety after the high-load events porting workforce and has already carried out worldwide.

modifications have been developed on FBW aircraft. encountered by their airplanes, and that additional broader and flights across European countries. The company operates one of the biggest

Severe turbulence can induce significant altitude excursions be- more-detailed inspections were required to ensure safety. The company has dedicated teams and all and most distinctive Boeing 737-VIP fleet

cause of the turbulence or as a consequence of triggering the Vmo/ The NTSB wants to prevent inspected but still unairworthy the resources necessary to perform transpor- worldwide, and is conveniently based globally.

Mmo protection or the AOA protection. Without the pilot in the aircraft from returning to service after events that exceeded the tation meeting the highest safety and security KlasJet is a part of Avia Solutions Group, the

loop these protections will place a priority on protecting the target manufacturer’s threshold. Furthermore, the board is troubled that standards. largest aerospace service company in Central

speed rather than maintaining the trajectory. When either protec- aircraft may be exceeding design and certification standards more KlasJet has been repatriating citizens since and Eastern Europe that serves over 2 000

tion law is activated, the autopilot is disconnected automatically. frequently than was known or expected, and recommends all such the beginning of this destructive situation and clients worldwide and collectively holds more

The pilot should apply smooth corrections to manage the aircraft events be tracked and evaluated. is fully prepared to co-operate with compa- than 500 licenses for its diverse activities. Q

trajectory and avoid sudden corrections fighting the turbulence. After encountering significant turbulence or any other event that WOMEN IN

According to the industry’s Upset Recovery Manual, if during re- may have exceeded the aircraft’s structural limitations, a captain

covery the application of full lateral control (ailerons and spoilers) is responsible for annotating the fact in the aircraft’s logbook after AVIATION

is insufficient, it may be necessary to apply rudder in the direction the flight, triggering a mandatory inspection for structural damage.

of the desired roll. The manual warns, “only a small amount of According to Airbus, turbulence can be considered as excessive
rudder input is needed. Too much rudder applied too quickly or when passengers and crew are moved violently against their seat belts FIRST ALL-FEMALE
held too long may result in loss of lateral and directional control and objects move around the aircraft. Inspections that are mandated

and cause structural damage.” after flight in excessive turbulence are described in the AMM.

After recovering the aircraft, flight crews must assess any dam- In case of severe turbulence, it is recommended the manufactur-
age that may have occurred. er be informed as well. Note that in some cases the manufacturers HELICOPTER TEAM

Severe atmospheric turbulence and inappropriate flight-crew have determined that limit loads have been exceeded in portions

control inputs can induce significant “multi-axial” loads on aircraft of the aircraft, thus requiring additional inspections. Q

women due to an increase of female Coast
Guardsmen at the unit.
he first all-female helicopter Coast "The Coast Guard is striving to increase

TGuard unit in McKinleyville soared the the number of women in the organization
skies recently, officials said. overall, not only in aviation,” said Lt. Audra

The McKinleyville Coast Guard unit is high- Forteza, a Sector Humboldt Bayaircraft

lighting their first all-female helicopter crew in commander.

celebration of Women’s History Month. "It's wonderful that our small unit has

According to Women In Aviation Interna- enough females that we can show young

tional, "while the amount of women in the women in the community that they do have

U.S. Aviation Field is still small with women these kinds of opportunities and hopefully

only representing about seven percent of the we can inspire them to pursue their career

total pilot population, the number of women dreams and grow up to be whatever they
involved is steadily increasing and women are want to be."

represented in nearly every aviation occupa- Sector Humboldt Bay's area of responsibility

tion today." consists of 250 miles of rugged coastline from
Coast Guard Sector Humboldt Bay was able the Mendocino-Sonoma County line north to
to achieve an aircrew consisting solely of the California-Oregon border. Q

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