Human Performance and Limitations
Vision, hearing, information processing, attention and perception, memory, claustrophobia and physical access.
Human performance & limitations, summary notes
- Vision is the dominant sense for inspection tasks but degrades in poor lighting, low contrast, glare and with age (presbyopia), this is why visual inspection standards specify minimum illumination and viewing distance.
- Hearing loss from unprotected exposure to engine run-ups and hangar noise is cumulative and irreversible, hearing protection is a human factors control, not just a comfort item.
- Information processing follows input (senses) → central processing (attention, memory, decision) → output (action); a bottleneck or overload at any stage increases error probability.
- Short-term (working) memory holds roughly 5-9 items for under a minute, this is why a technician who is interrupted mid-task frequently loses their place, and why written work cards exist instead of relying on memory.
- Confined spaces (fuel tanks, wheel wells) can trigger claustrophobia and restrict physical access and dexterity, raising the chance of a rushed or incomplete inspection.
- ⚠ Exam trap: an interruption wipes working memory (~5-9 items), write the number down; and expectation shapes perception, so a briefed inspector detects more.
A technician is asked to remember a 6-digit work order number while also being asked a question by a supervisor. They mis-key the work order afterwards. Why?
Working memory has limited capacity and decays quickly, especially when a competing task (answering the supervisor) interrupts rehearsal, the fix is to write the number down immediately rather than hold it in memory.
Performance & limitations concept map
Human Performance & Limitations
Human performance quiz
Human Performance and Limitations, quiz
1. Which sense is most relied upon for visual inspection tasks such as crack detection?
VisionHearingTouch2. Hearing loss from repeated unprotected exposure to hangar and engine-run noise is best described as:
Cumulative and irreversibleFully reversible with restOnly a short-term inconvenience3. Roughly how many items can short-term (working) memory reliably hold for under a minute?
5-9 items20-30 itemsUnlimited, given enough attention4. A technician interrupted mid-task by a phone call often loses track of which step they were on. This illustrates a limitation of:
Working memoryLong-term memoryColour vision5. Working in a confined space such as a fuel tank can trigger claustrophobia, which primarily affects:
Access, dexterity and thoroughness of the workOnly the technician's long-term hearingNothing, if the technician is experienced6. The age-related loss of near-focus that affects close inspection work is called:
PresbyopiaTinnitusVertigo7. Information processing is usually modelled as input (senses) → central processing → :
Output (action)Storage onlyNothing further8. Perception can mislead an inspector because the brain:
Fills in expected detail and can 'see' what it expectsRecords everything perfectlyIgnores training entirely