Reading a Claim in a Technical Passage
An apprentice is given a short passage to summarise for a briefing:
"Although composite materials are lighter than aluminium alloys and resist corrosion better, they do not deform plastically before failing. A metallic panel that is overloaded will bend and give visible warning; a composite panel may appear sound until it fractures suddenly. Consequently, inspection intervals for composite structures are often shorter, and inspectors rely on techniques such as tap testing and ultrasonic scanning rather than visual checks alone. This does not mean composites are unsafe - only that their failure mode demands different inspection habits."
The apprentice's draft summary reads: "Composites are unsafe because they fail without warning, so they should be avoided in aircraft structures."
1. Identify the specific errors in the apprentice's summary by contrasting it with what the passage actually states.
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The summary contains two clear distortions:
- 'Composites are unsafe' - the passage explicitly says the opposite: 'This does not mean composites are unsafe - only that their failure mode demands different inspection habits.' The apprentice has turned a caution about inspection into a verdict on safety.
- 'Should be avoided in aircraft structures' - the passage never recommends avoidance. It describes a real advantage (lighter, more corrosion-resistant) and a real drawback (no plastic warning before fracture), then draws a conclusion about inspection practice, not about whether to use the material.
The apprentice has also dropped the passage's balanced structure, keeping only the negative half.
2. Rewrite the summary in two sentences that preserve the passage's actual argument, and name the reasoning error the apprentice committed.
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Model rewrite: 'Composites are lighter and more corrosion-resistant than aluminium alloys, but they fail suddenly without the plastic warning a metal gives. This does not make them unsafe; it means they require shorter inspection intervals and techniques like tap testing and ultrasonic scanning rather than visual checks alone.'
The reasoning error is overgeneralisation from a single drawback (also describable as a false dilemma - treating 'has a difficult failure mode' as 'must be avoided'). The passage's own qualifier - 'only that their failure mode demands different inspection habits' - is the sentence the apprentice ignored.