339A Mobile Crane Operator Exam: 2026 Weighting Guide
The Red Seal Mobile Crane Operator (339A) Interprovincial Examination contains 110 multiple-choice questions, distributed across 7 Major Work Activities (MWAs). Knowing how those questions are split is the difference between studying evenly and studying where the marks actually are.
Mobile Crane Operator (339A) Exam Breakdown (Official)
- Total Exam Questions: 110 multiple-choice questions
- Major Work Activities: 7 (A–G)
- Source: Red Seal Exam Breakdown — Mobile Crane Operator (339A), red-seal.ca
- Time allowed: 4 hours — the same for every Red Seal trade, whether the paper is 100 or 150 questions
- Passing mark: 70% (77 / 110 correct)
- Time and pass mark are set provincially, not by the Red Seal Occupational Standard. Confirmed against Skilled Trades Ontario and SkilledTradesBC.
1. Question count by Major Work Activity
The figures below come directly from the official Red Seal breakdown:
| Major Work Activity | Share | Questions |
|---|---|---|
| MWA A Performs common occupational skills |
6% | 7 Qs |
| MWA B Performs hoisting calculations |
18% | 20 Qs |
| MWA C Inspects and maintains crane |
13% | 14 Qs |
| MWA D Performs rigging |
12% | 13 Qs |
| MWA E Plans lift, prepares site and sets up crane |
15% | 16 Qs |
| MWA F Assembles, disassembles and transports crane |
14% | 15 Qs |
| MWA G Operates crane |
23% | 25 Qs |
2. What the weighting tells you to study first
The two heaviest blocks carry 41% of the paper between them: MWA G (Operates crane, 25 questions) and MWA B (Performs hoisting calculations, 20 questions). Prioritizing high-weight blocks first builds your cushion toward the 77-question pass threshold.
A practical priority sequence by exam weight is: G → B → E → F → C → D → A, adjusted for which areas you perform least often on the job.
3. Three questions at exam standard
These are representative questions from the Red Seal Pass Mobile Crane Operator (339A) bank (1,100 questions total), shown with worked explanations:
If a mobile crane must operate with outriggers extended to the manufacturer intermediate (mid-span) position, which load chart must be consulted?
- A) The full-outrigger chart with fifty percent deducted across all boom lengths.
- B) The dedicated mid-span outrigger capacity chart provided by the manufacturer.
- C) The on-rubber chart multiplied by two to reflect partial outrigger support.
- D) The standard full-capacity chart with radius limited to thirty-five feet.
Answer: B
Mid-position outrigger operations require a specific mid-span load chart calculated by the manufacturer. Arbitrary percentage deductions from full-span charts are strictly prohibited.
When reeving a multi-part hook block, why is 'skip reeving' or symmetrical reeving preferred over simple consecutive side-to-side reeving?
- A) It centers the traveling block beneath the boom head, preventing hook block tilting and twist.
- B) It increases the operating line speed of the hoist winch by twenty-five percent.
- C) It eliminates the need for an anti-two-block limit switch weight on the boom tip.
- D) It allows the operator to hoist loads using wire rope of two different diameters.
Answer: A
Reeving sheaves consecutively across one side creates high friction and line tension on one half of the block, causing the block to hang tilted or twist (cabbing). Symmetrical or skip reeving balances line pull across the block center.
How must the crane operator test the operational function of the anti-two-block (A2B) switch during the pre-shift setup inspection?
- A) Observe whether the anti-two-block warning flag swings freely in the outdoor atmospheric breeze.
- B) Hoist the hook block at maximum speed into the boom tip sheave until the wire rope snaps.
- C) Disconnect the electrical wiring harness and check continuity using a 120-volt test light.
- D) Manually lift the A2B weight and confirm audible/visual alarms trigger and hoist motions lock out.
Answer: D
Testing the A2B requires gently lifting the counterweight by hand (or with an assistant) to slacken the chain. The operator confirms that cab alarms trigger immediately and that all hazardous hoisting motions (hoist up, telescope out, boom down) lock out.
4. How to practise against this blueprint
Our Mobile Crane Operator (339A) practice quiz starts with 10 interactive readiness questions with worked explanations and step-by-step trade math, and our full bank contains 1,100 questions with spaced-repetition review. The full 110-question timed mock exam is calibrated to the exact MWA split above so your diagnostic report shows which activity is costing you marks.
Next step for your Mobile Crane Operator (339A) exam
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Mobile Crane Operator (339A) 10-question readiness quiz · Full 110-question timed mock exam
🎧 Watch & Listen: 30 Mobile Crane Operator (339A) Practice Questions & Worked Answers
Weighted to the official Red Seal Mobile Crane Operator (339A) exam breakdown, read aloud with a 5-second pause before each worked answer and code explanation.
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Is Mobile Crane Operator (339A) certification required where you work? Check the rules for British Columbia, Ontario or Alberta.