WORKLOAD MANAGEMENT BY FLIGHT CREW

Key to conducting a flight efficiently and safely is to effectively manage the workload one is faced with during different phases of the flight.
Flight crew workload is typically shared between a Captain and a First Officer.Whilst one takes up the mantle of pilot flying, the other crew carry out the pilot not flying/ pilot monitoring duties.
Workload management is regulated within the frame work of operations by promulgating standard operating procedures, task sharing principles,time management and so on.

Workload is the highest for flight crew during preflight, taxi out, take off and climb to cruise level, before top of descent, during descent, approach, landing and taxi in to bay.
Procedures detailed ensure that they clearly define various tasks carried out during these times and by whom it is executed to regulate the workload and lessen the burden.

Not withstanding the above, during emergency and multiple emergency situations, despite the crew being trained in handling situations in various scenarios, one is faced at times with situations wherein the crew need to dig deep and face occasionaly tremendous increase in their workload, also termed as task saturation. Only way to manage highly increased loads is to prioritise the tasks, work  with fellow crew,share the work  load and seek similar assistance from cabin crew, ground control and others , to manage the emergency to ensure a safe landing.
Workload management forms part of Crew resource management(CRM) training and equips one with dealing in situations which he hasn't dealt before.

AIRCRAFT EVACUATION-- EMERGENCY COMMUNICATION

KUCHEMANN'S CARROTS

A

s we do the pre-flight walk around , and inspect  the wing underside we rarely give a second glance at the canoe shaped flap track fairings under the wings. Some are slender but many appear somewhat oversized to accommodate just  the flap fairings. Or do they serve some other function?

The physics of airflow alteres violently as it expands from subsonic to supersonic speeds. As the aircraft passes through the transonic speed range, local airflow approaches sonic speeds over the wing and body of the aircraft and leads to the formation of shock waves and consequent large increase in drag.

At transonic speeds, it was found, that the time-honoured principle that the drag of the individual elements of an airplane could be added in a linear manner to give the approximate drag of the entire configuration could no longer be relied upon.

Researches by Dietrich Kuchemann in the UK and Richard Whitcomb of NASA , in early 1950s, established that this wave drag can be minimised by a fuselage wing configuration synthesis, where the cross sectional area changed smoothly along the length of the aircraft. Known as the Area Rule, its basic tenet postulates that the wave drag of a simple equivalent body of revolution would be the same as a more complex wing body arrangements.

Initial  application of area rule designs can be seen in the   “Coke Bottle” or “Marylin Monroe” indented fuselage body shapes to reduce the effect of the presence of wings as in F-102 and F-106 aircraft. This, however had practical limitations and alternate efforts to address the local discrepancies in cross sectional areas led to the concept of attaching conical and pod shaped bodies along the wing , nacelle and fuselage. First successful application of this principle to combat wave drag effects was in Convair- 990. Following applications of the local area rule, several pylon, nacelle, and wing fairings were embodied, to smooth out the area distribution and facilitated in raising the cruise speed from 0.8M for the basic aircraft to 0.89 M for the modified airframe.

 These anti shock bodies  christened as ‘Whitcomb After-bodies’ or ‘Kuchemann’s Carrots’ are widespread in today’s designs.

Anti shock bodies were also apparently developed by the Soviet Designers during the same time , as seen in their installations in TU-16 and through subsequent designs such as the TU 154.

On most modern designs, the mechanism for deploying the wing flaps are encased in canoe shaped pods , which serve as anti-shock bodies and can be seen in A300/310, A 380 and Boeing 757 to name a few. Known to most as flap track fairings, garnering little attention, these pods nevertheless have an important role in transonic drag reduction and fuel economy.

WINGLETS

It’s a nearly vertical airfoil at an airplanes wingtip that reduces drag by inhibiting turbulence.

( Merriam-Webster dictionary)

First known use of winglet dates back to as early as 1611.

EVOLUTION OF WINGLET

NASA’s pioneering research in the 1970’s as part of energy efficiency program to conserve energy in aviation resulted in Winglets finding acceptance with airplane manufacturers and airlines alike.

Richard Whitcomb was instrumental in conducting test to explore hypothesis that a precisely designed vertical wingtip device could weaken wing tip vortices and thus diminish induced drag which translates into less fuel burn and better cruise efficiency.(NASA website)

American, Southwest, Ryanair, and others took advantage of fuel efficiency that comes with winglets and partnered with Boeing –Aviation Partners group(ABP) to have winglets installed.

Wing Tip fence

Wingtip fence is the preferred device of Airbus to tackle and reduce induced drag on wingtip.Airbus also has ambitious project in introducing Sharklets, akin winglets on its A320 neo and also an active proposal for the same to be introduced on A330.

AERODYNAMICS OF WINGLET

Winglets

Lift is the force that makes the aircraft fly. Lift is a result of unequal pressure in a wing as air flows around it with positive pressure underneath the wing and negative pressure above.

Drag is the resistance encountered while moving through the airflow. Considerable amount of drag is also generated from the high pressure under the wing, which causes air to flow up over the wing tip and spin off in a vortex.. These vortices produce what is called induced drag which hampers aircraft fuel consumption, range, speed and so on.

Sharklets

 Hence, the primary aim of winglet is to break the wing tip vortices and reduce the induced drag and increase aircraft performance. Fuel savings are estimated between 4-6% by employing winglets.  Initial results as released by airbus for A330 program indicate fuel saving in excess of 3.4% and increased take off weight. Also, the noise footprint will be reduced along with better carbon footprint in light of emissions being the centre stage of aviation policies.
(Acknowledgements: Airbus, NASA and Merriam-Webster)

INITIATION OF EVACUATION