DGCA Technical General: Structures Questions
160 exam-style Structures questions for the DGCA Technical Generalpaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
In a non-stressed skin aircraft, bending loads acting on the wings are taken by
- A Skin
- BSpars
- C Stringers
- D Ribs
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Correct answer: B. Spars
In a non-stressed-skin (framework) wing the skin only provides the aerodynamic shape, so the wing bending loads are reacted entirely by the spars, which act as the principal spanwise beams. The ribs, stringers and skin carry little of the bending.
- Q2
An aircraft that has been designed for long haul operations cannot be used for short haul because?
- AIt will have an uneconomical seating arrangement.
- BSeparate JAR certification is required for each type of operation.
- CThe structure is not designed to sustain the different life cycle stresses patterns of short haul operations.
- DThe aircraft will have too much fuel capacity and too little payload capacity.
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Correct answer: C. The structure is not designed to sustain the different life cycle stresses patterns of short haul operations.
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- Q3
411.When an aircraft structure is designed according to fall safe philosophy it means
- A The structure will never break regardless of stress applied
- BThe failed structure can be replaced easily
- CAdjacent structure withstand the loads which failed structure
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Correct answer: C. Adjacent structure withstand the loads which failed structure
A fail-safe structure provides redundant load paths, so that if one structural member fails, the adjacent structure temporarily carries the loads the failed member was supporting until the damage is found and repaired. It does not mean the structure can never break, only that a single failure is not catastrophic.
- Q4
In a stressed skin aircraft, bending loads acting on the wings are taken by
- A Ribs and stringers
- BStringers and spars
- CSpars and skin
- D Spars and stringers
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Correct answer: C. Spars and skin
In a stressed-skin wing the working skin is bonded into the structure so that the skin and the spars together react the wing bending loads, the skin carrying tension and compression as part of the load path. This lets the structure be lighter than a spar-only design.
- Q5
Fail safe structures?
- AAre designed to remain safe for a specified number of hours or flight cycles.
- BAre designed such that if any element of structure fails, the loads will be carried by the adjacent elements of structure.
- CAre designed such that all parts that are likely to fails are inspected regularly.
- DDo not require regular inspection.
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Correct answer: B. Are designed such that if any element of structure fails, the loads will be carried by the adjacent elements of structure.
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- Q6
469.Why do windshield consist of five layer
- ATo prevent fatigue
- B To enable effective heating
- CTo increase their impact resistance
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Correct answer: C. To increase their impact resistance
The windshield is laminated from multiple glass and vinyl plies so it can absorb bird-strike and pressurisation loads; the five-layer sandwich gives high impact resistance and remains fail-safe if a single ply cracks.
- Q7
501.How are wing bending moments reduced in flight?
- A By having wing mounted engines and using the wing fuel first
- BBy using ailerons "up-float" and using centre tank fuel as late as possible
- CBy using alieron "up-float" and using wing fuel as late as possible
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Correct answer: C. By using alieron "up-float" and using wing fuel as late as possible
Lift bends the wings upward while weight carried in the wings bends them down, so keeping wing fuel on board as long as possible (burning centre-tank fuel first) and rigging the ailerons to float slightly up, which trims lift off the outboard wing, both reduce the wing-root bending moment.
- Q8
The ‘torsion box’ of a modern aircraft wing structure consists of:
- ASpars, skin, frames and stringers
- B Spars, skin, frames and ribs
- C Spars, skin, longerons and ribs
- D Spars, skin, stringers and ribs
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Correct answer: D. Spars, skin, stringers and ribs
The torsion box that forms the primary structure of a modern wing is built from the spars, the skin panels, the spanwise stringers stiffening that skin, and the ribs that maintain the aerofoil shape. Together these carry the wing bending and torsional loads.
- Q9
Trim tabs ?
- AReduce manoeuvring forces.
- BTrim the aircraft in normal flight.
- CTrim the aircraft in low speed flight.
- DReduce or cancel out control hinge moments.
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Correct answer: D. Reduce or cancel out control hinge moments.
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- Q10
The function of stringers in the construction of the fuselage is:
- A To withstand shear stress
- BTo provide an attachment for insulation
- C To provide support for the skin and to absorb some of the pressurization strain as tensile loading
- D To provide an alternate load path in the event of the failure of a frame.
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Correct answer: C. To provide support for the skin and to absorb some of the pressurization strain as tensile loading
Stringers run spanwise along the fuselage to stiffen and support the skin, and in a pressurised structure they also share some of the pressurisation loads by carrying tensile stress. This keeps the thin skin from buckling and helps distribute the hoop and longitudinal loads.
- Q11
A Q-fell unit would be connected?
- AIn parallel with the rudder control.
- BIn series with the aileron control.
- CIn parallel with the pitch control.
- DIn series with the pitch control.
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Correct answer: C. In parallel with the pitch control.
This Explanation is Coming Soon
- Q12
Long haul aircraft are not used as short haul aircraft because
- A Checklists would be too time consuming to complete
- B It would use too much fuel
- C Some tanks will be empty the whole time imposing too much strain on the aircraft
- D Structures are given fatigue lives based on their use
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Correct answer: D. Structures are given fatigue lives based on their use
Aircraft structures are assigned fatigue lives based on the number and type of flight cycles they experience, and a long-haul aircraft flown on short sectors would accumulate pressurisation and load cycles far faster than intended, eating up its fatigue life prematurely.
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