Cabin Floor Research Articles

Physical workload of flight attendants when pushing and pulling trolleys aboard aircraft

The musculoskeletal loads from moving trolleys aboard aircraft were assessed by observation of trolley handling on planes and by physical workload analyses of pushing and pulling of trolleys in a laboratory set up. Trolley handling by a total of 15 female flight attendants was observed on 10 short- and medium-distance flights in different types of aircraft. About 25 selected flight attendants (22 females; 3 males) of five German airlines took part in the laboratory study, which comprised three-dimensional (3D) measurements of posture and hand forces during pushing and pulling of trolleys in a variety of configurations. From the on-flight observations performed, between 150 and 250 trolley movements can be projected for a work shift. The greatest physical workload is to be expected at the beginning of service: The trolleys are fully laden then, and the cabin floor can still be inclined up to 8°, as the aircraft is still climbing, particularly on short-distance flights. The laboratory investigation revealed that the musculoskeletal workload from pushing and pulling depends essentially on the trolley load and on the gradient of the cabin floor. In addition, the degree of stressing depends significantly on the trolley type, mode of handling and personal dexterity. The up/down force component perpendicular to the direction of motion often achieved considerable amplitudes-in some cases equal to or exceeding the force in the direction of movement. The posture analysis demonstrated that pulling forced the flight attendants to adopt ergonomically unfavourable postures such as pronounced flexion of the back, particularly among female subjects. The highest values for flexion of the back occurred while pulling the half-size trolley. The results demonstrate that female flight attendants are likely to overload themselves if they frequently have to move heavily laden trolleys unaided on an inclined cabin floor. Relevance to industry On short distance flights, flight attendants have been complaining increasingly of high physical workload from manoeuvring trolleys. On the basis of the presented data airline companies may improve the trolley handling skills of their flight attendances by practical trainings and may ergonomically optimize the general service procedures aboard aircrafts.

Investigation of possible control options lateral movement of military transport aircraft on the landing stage monocargo

A рossibiliti of pilotage of moment parameters ot military-transport aircraft on the stage of monocargo landing is being examined. Fully mathematic noneline model of the aircraft wilh consideration of the influence of monocargo onto the cargo cabin floor has been specified. Mathematic modelling of monocargo landing process by stabilisation of given route of the aircraft under normal and turbulent air conditions has been made.

Attempts to Standardise Vibration Measurements in a Single-Grip Harvester

Forest harvesters are machines used for felling, delimbing, cross cutting, and sorting of trees in the Nordic countries. During these operations, the operators are exposed to vibration generated from the working process. This study measures the transmission of vibration from the crane to the cabin and to the driver's seat in a harvester during delimbing and felling with varying angles between the crane and machine. Moreover, this study suggests a way to conduct these measurements with a repeatable method. The vibration levels decreased in each step in the vibration chain “crane foot — cabin floor — seat”; less than 10% of the vibration reached the seat pad. The angle between the crane and machine had only minor effects on the transmission. The experimental method used for measuring the vibration seems to give a good opportunity to conduct standardised measurements for different work elements.

Transit care of the ventilated critically ill in commercial airliners

Air ambulances and customized military aircraft are established modes of transporting critically ill patients. Defence services and aid agencies even have flying hospitals, replete with operating theatres and ICUs. With burgeoning travel by an increasingly elderly population, a growing number of travelling Australians suffer critical illnesses overseas. Transcontinental air ambulances are prohibitively expensive and many American and European commercial airlines ban travel by seriously ill patients. Transit intensive care on board commercial airline flights poses complex physiological and logistic challenges. We have transported hundreds of critically ill patients and report on 10 episodes of aero-intensive care with IPPV on board scheduled passenger services. These were from the Philippines, the USA, the United Kingdom, Thailand, France, Norway and Austria on Qantas, Singapore Airlines, Thai Airways and Malaysia Airlines. The aviation environment imposes a bewildering array of electronic, safety and security related issues to be overcome. The entire mobile ICU weighs 100 kg. A vacuum-mattress on a stretcher fitted to the cabin floor at the rear of the economy-class cabin and screened off from the other passengers ensures patient privacy (Fig. ​(Fig.1).1). Oxygen is scarce and extremely expensive during flight. We employed the 'circle system' with a CO2 absorber and in-line oxygen analyser. Mobile suction, infusion pumps, transit-care monitors and portable blood gas analysers were all adapted for use in commercial aircraft. Figure 1 Australia and New Zealand lead the world in transit care of the critically ill in commercial airliners.

M.C. Gill wins airline floor contract

SOUTHWEST Airlines in the USA has awarded a long term contract to M.C. Gill Corp for composite cabin floor panels for use during maintenance checks on its aircraft. This is a short news story only. Visit www.reinforcedplastics.com for the latest plastics industry news.

A modern aerospace modeling approach for evaluation of aircraft fuselage crashworthiness

A 9 [m/s], (30-ft/s) vertical drop test of a fuselage section of a Boeing 737 aircraft was conducted at the FAA William J. Hughes Technical Center in Atlantic City, NJ. Test was performed to evaluate the structural integrity of a conformable auxiliary fuel tank mounted beneath the floor and to determine its effect on the impact response of the airframe structure. The objective of the test was to determine the interaction between a typical transport aircraft fuselage, particularly its floor structure, and a conformable auxiliary fuel tank under severe, but survivable, impact conditions. The fuel tank used in this test is representative of tanks being installed in narrow-body transport aircrafts. The 3 [m], (10-foot) airframe section from a Boeing 737-200 aircraft was dropped from a height of 4.27 [m], (14-feet) generating a vertical impact velocity of 9 [m/s], (30-ft/s). The airframe test section weight of 3,982.5 [kg], (8780-lb) simulated the load density at the maximum takeoff weight condition. The weight included cabin seats, dummy occupants, and simulated fuel in the 1,892.71 liters, (500-gallon) fuel tank. Structural response data were obtained during the impact from instrumentation installed on the fuselage structure, floor structure, and the fuel tank. The fuselage test section sustained severe damage after the test. Portions of the cabin floor were damaged due to the impact with the auxiliary fuel tank located in the cargo compartment. Portions of the fuselage bottom were crushed by approximately 66 [cm], (26-in). The bottom of the fuel tank was punctured in numerous locations causing fuel to leak out. The strength and rigidity of the fuel tank limited the inherent ability of the fuselage structure to absorb energy crushing during the impact. The test data were used to compare with a finite element simulation of the fuselage structure and to gain a better understanding of the impact physics through analytical/experimental correlation. To perform this simulation, a full-scale 3-dimensional finite element model of the fuselage section was developed using the explicit, nonlinear 3-D Finite Element code, LS-DYNA. The emphasis of the simulation was to determine the structural deformation and floor-level acceleration responses obtained from the drop test of the B737 fuselage section with the auxiliary fuel tank.

Crashworthiness of helicopter subfloor structures

To improve a helicopter design concept, which meets structural and crashworthiness requirements, a research program is undertaken to study the energy absorption capability of a subfloor structure. In particular, crash tests are performed on the subfloor structure and on the intersection elements, which are components of the structure and can create high deceleration peak loads at the cabin floor level causing dangerous inputs to the occupants. Then the structures are analysed by a commercial explicit finite element code, PAM-CRASH, using detailed geometrical models, suitable materials models and the appropriate definition of contact forces and rivets. The analysis shows that the load-shortening diagrams present a good correlation to the experimental data and that the structural collapse predictions correspond closely to the observed behaviour during the experimental tests. Consequently the finite element analysis can be used to aid the designers in evaluating the crashworthiness of different structural concepts and can therefore be an important mean of reducing development costs.

Easing the Strain

This article focuses on the finite element analysis (FEA) that is a key ingredient in keeping a popular theme park ride up and running. Long before the ride entered service, Universal called in GLENCO Engineering Inc., to perform finite element modeling and analysis in order to evaluate the primary structural components of the Spider-Man ride vehicle cabin. The FEA initiated to increase the stiffness of the cabin floor also identified a location where the peak strains were higher than the values determined in the hand calculations and associated strain gauge testing. The FEA of the Spider-Man cabin structure significantly improved the design of the composite floor. Strains measured at locations selected without the benefit of FEA produced a misleading assessment of the design in its first prototype. FEA, however, identified peak strains at a location and direction that were not intuitively obvious to the engineers. The results were confirmed with dynamic strain measurements—verifying not only magnitude but also directions of the principal strains. The finite element model was a valuable tool that enabled the floor design to be precisely refined in one of the iterations.

Horizontal vibration suppression method suitable for super-high-speed elevators

Horizontal vibrations of elevator cars mainly occur because a car swings as roller guides installed at corners of a car frame move on a winding guide rail at high speeds. Rider comfort in high-speed elevators is worsened by these vibrations. Conventional active dampers suppressing horizontal vibrations using ac servomotors make cars heavier so driving power becomes larger, and they are not easily applied to existing elevators. An active damping control method suited to super-high-speed elevators is described which can solve these problems. The method suppresses vibrations by generating only enough magnetic force needed to suppress them only when vibrations of the car frame are produced. The vibrations are detected using acceleration detectors and magnets installed on the left and right sides of the car frame. A computer simulator was made to analyze phenomena of car vibrations and to verify effects of the proposed magnetic damping controller. It was found that the vibrations generated on the cabin floor were remarkably large when the left and right sides at the upper and lower parts of the car frame were swung by sine waves with the same phase. The vibrations had two resonant modes. Results obtained with the computer simulator and a full-scale running simulator showed that the acceleration on the cabin floor, even at the resonant frequencies, could be reduced by the magnetic damping control to around 0.1 m/s2 which would provide a comfortable ride. © 1999 Scripta Technica, Electr Eng Jpn, 129(1): 59–73, 1999

Interior acoustics of a truck cabin with hard and impedance surfaces

Interior acoustics of a truck cabin is determined and the consequences of an attempt, which was performed with acoustic linings in order to improve the interior comfort, are presented. Acoustic field generated from the harmonic vibrations of the cabin floor panel was expressed by the Helmholtz integral equations. Numerical results were obtained by a computer code which was developed in Visual Basic programming language in order to solve the integral equations by using boundary element method. The effects of the linings on the levels and distributions of the sound pressure in the cabin are presented by means of the comparison of the results calculated from two different boundary conditions: hard wall and impedance wall.

Crashworthiness of helicopter subfloor structural components

The present investigation is oriented towards the design of an energy absorbing aluminium subfloor for a new Agusta helicopter. To identify the detailed design and the structural concepts for the most efficient mechanism of energy absorption, the typical subfloor components have to be investigated. Design aspects focus in more detail on the subfloor structural intersections, because, under vertical crash loads, they can create high deceleration peak loads at the cabin floor level and cause dangerous inputs to the seat/occupant system. The crash behaviour and energy absorption capability of the subfloor structural intersections are investigated by experimental drop tests and finite element analyses. Presents the correlation between crash data and numerical results.

Horizontal Vibration Suppression Method Suitable for Super-High-Speed Elevators

Horizontal vibrations of elevator cars mainly occur because a car swings as roller guides installed at corners of a car frame move on a winding guide rail at high speeds. Rider comfort in high speed elevators is worsened by these vibrations. Conventional active dampers suppressing horizontal vibrations using ac servo motors make cars heavier so driving power becomes larger, and they are not easily applied to existing elevators. An active damping control method suited to super-high-speed elevators is described which can solve these problems. The method suppresses vibrations by generating only enough magnetic force needed to suppress them only when vibrations of the car frame are produced. The vibrations are detected using acceleration detectors and magnets installed on left and right sides of the car frame. A computer simulator was made to analyze phenomena of car vibrations and to verify effects of the proposed magnetic damping controller. It was found that the vibrations generated on the cabin floor were remarkably large when left and right sides at the upper and lower parts of the car frame were swung by sine waves with the same phase. The vibrations had two resonant modes. Results obtained with the computer simulator and a full scale running simulator showed that the acceleration on the cabin floor, even at the resonant frequencies, could be reduced by the magnetic damping control to around 0.1m/s2 which would provide a comfortable ride.

“In‐service” aircraft inspection and non‐destructive testing

Consider an aircraft in the throes of major maintenance. With access panels, cover panels, fairings, galley units, seats, interior trim removed, primary structure, electrical and hydraulic systems together with all the other complexities which make up a modern flying machine are revealed. Lift the cabin floor to find a multitude of control systems, look into the electronics bay at racks of black boxes, large looms of multi‐coloured cables and a certain perspective about the importance of organised and systematic approach to inspection of aircraft begins to emerge. Clearly the broad brush approach is neither appropriate nor likely to be effective.

Structural influence of the cabin floor on sound transmission into aircraft - Analytical investigations

The structural influence of the cabin floor on the transmission of low-frequency propeller noise into aircraft interiors has been examined using a simplified analytical model. The response amplitudes and distributions of shell displacement and internal acoustic pressure are examined for various frequencies and floor configurations. In general, at lower frequencies, the floor exerts little structural influence on the transmission of acoustic energy to the interior. However, as the frequency nears half the cylinder ring frequency, the floor can be seen to alter significantly the internal pressure distributions and response.

Engineering ethics: How to be ethical and survive: Some engineering societies offer aid in a conflict, but competence and confidence can help mitigate trauma and duress

Engineers sometimes find that attempts to practice their profession ethically can lead to conflicts with their managers. Where such conflicts have involved the public safety, dramatic confrontations have resulted. Here are well-known examples: ? In 1972 in San Francisco, a Bay Area Rapid Transit train overran a station and plowed into a sandpile. Immediately questions were raised publicly about the safety of the new system's automatic features. The accident was traced to a crystal oscillator in an operating subsystem that had transmitted the wrong speed to the train. Costly corrective retrofitting and a backup system were ordered, but critics said there were design flaws that should have been caught before the railroad line was built. ? In 1974a Turkish Airlines DC-10 crashed nine minutes after takeoff from Paris when the jet's rear cargo door flew off at 13 000 feet. The sudden decompression crushed the cabin floor and the plane's hydraulic steering apparatus. In all, 346 persons died. Again, a public controversy erupted, with critics charging that the builders of the craft and even the U.S. Federal Aviation Administration knew that the door design was defective. The latching mechanism and the omission of floor venting were problems that could have been corrected at low cost when recognized during the design phase. The cost rose steeply as designs were converted to production processes and then to airplanes.

Engineering Economy Class Passenger Seating for the Standard and Super VC10s of B.O.A.C.

A Review of Developments in Aircraft Seating in Recent Years and a Description of the Engineering and Commercial Requirements which Affected the Choice of Suitable Seating for Britain's Latest Long‐Range Civil Airliner. AIRCRAFT seats to the aircraft engineer have usually referred, in the past, to those somewhat necessary last minute evils that are attached to the cabin floor and are often found very useful for the parking of tool boxes and other maintenance impedimenta. When it is considered that on present day inter‐continental jets the passenger has to ‘live in’ the scat for 28 hours on a typical London/Far East flight without such luxuries as the leisurely night stops of ten years ago, it will be appreciated how important seat design and comfort can be.

Aircraft Systems

Details of the Hydraulic, Engine Control, Electrical, Fire Protection, Flight Control, Air Conditioning and Cabin Pressurization, Ice and Rain Protection, Radio and Auxiliary Power Plant Systems. IN order that high utilization rates and low maintenance costs may be achieved it was necessary to match the fail‐safe, long‐life structure of the HS.748 to trouble‐free systems. The system design philosophy adopted on the Hawker Siddeley 748 was ‘avoid complication and use proven components wherever possible’. This approach together with a layout whereby external access is provided to all systems has produced easy and almost trouble‐free maintenance. The majority of the system components are installed under the cabin floor and are grouped as shown in Fig. 1. Access is through the landing gear doors or four large quick release elliptical access panels enabling all trades to work on the aircraft at the same time.

Gas Turbine Aero Engine Rotor Balance and Vibration

A Description of the Early Problems Encountered by Rolls‐Royce Ltd., which Led to the Appointment of a Specialist ‘Rotor Balance’ Engineer, and a Review of the Company's Current Balancing Techniques. THE advent of the gas turbine aero engine brought a state of passenger comfort, never before experienced, into the field of civil air transport; this was possible because the unbalanced forces due to reciprocating masses are entirely absent and the purely rotating masses of a turbine engine can, theoretically, be brought into perfect balance. The resulting smooth running engines produce lower levels of passenger fatigue due both to physical effects (i.e. a reduced feeling of ‘pins and needles’ in those parts of the anatomy touching the cabin floor or scat) and to aural effects (i.e. a lower noise level from engine buzz or cabin panels and fittings resonances).