6. How confortable has been your flight?
6.1 Noise and vibration
Who has already flown have experienced some difficulty to talk with other people or he has been bored from vibrations. Noise and vibrations inside the airplane cabin and cockpit have two principal sources:
- engine (direct noise or local turbulence induced by propeller or nozzle flow)
- airflow on the external surface of the fuselage (boundary layer)
Research on noise and vibration reduction on transportation
The direct and induced engine noise and vibration can be reduced by a well designed engine system and its transmission can be reduced by special material inside the engine nacelles and special materials inside the internal wall of cabin and cockpit (passive devises).
Applied research is going on for possible application of active reduction of noise and vibration, that is with mechanical and/or acoustics devises that work in counter phase with the original noise and vibrations.
6.2 Uncomfortable and oscillations
By a cabin window in an air transport airplane, wing oscillations can be seen some times in a flight. Passengers can experiment oscillation of the whole airplane up and down because of gust effects. Usually pilots make some little change to the route to avoid severe gusts. Besides that, oscillations about the airplane CG could occurs because of gust effect or because the so called pilot induced oscillation during a change in flight parameters.
Pitch, yaw or coupled oscillations can occurs that could cause discomfort to passengers or in some case even accidents (undamped pitch oscillations for examples). It is already said that fixed parts of the airplane tails tend to stabilize the motion.
Some examples of devices utilized to damp an oscillation in transportation
The tendency to return or not to the initial equilibrium is called static equilibrium problem. The way the airplane return to the initial equilibrium conditions is called dynamic equilibrium problem.The oscillation about Center of Gravity can be damped or not: if oscillation with decreasing amplitude occurs, we speak of airplane dynamically stable; if oscillation is maintained, we speak of airplane dynamically neutral; if oscillation with increasing amplitude, we speak of airplane dynamically unstable.
There are many applications in the today transport technology devoted to reduce uncomfortable or even dangerous oscillations.
6.3 Customer statisfaction
The quality that companies can assure in supplying their products or services is evaluated by means of a set of rules (as for examples ISO 9000 families) and the organization, which have issued those rules, give on demand to the companies, which are in compliance with those rules, an official acknowledgment (Accreditation/ Certification). What is important to remark is that the request of this acknowledgement is on voluntary basis and looking at the < Market > opportunities. In many Call for tender, participants are more and more often requested to have an Official Quality y Acknowledgment. In these last years great importance is given to the so called Customer Satisfaction criterion.
In the Air Transportation System Quality System is involving each relationship between two organizations, for examples between Airliners and Passengers, or between Manufacture Companies and Airliners.
A close up looking at aevaluation in the case of Airliners and Passengers, is evident that the passengers satisfaction of their flight is not only a matter of technical problems as noise and vibration inside the cabin, but and above all, of the behaviour of hostess and stewards or of the comfort/discomfort because of the narrow or the wide body fuselage, or the capability to respect the scheduled flight time. Moreover the passenger unsatisfaction could be amplified by psychological aspects as the fear of flying or health problems.
Compliance to safety requirements is mandatory for an airplane certification! Safety is not a problem of Customer Satisfaction, unlike cabin comfort.
