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newSchoolWorks.com › VoTechWorks › Building & Construction › Heavy Equipment Operation › Loader Operation › Lesson 3
BLD-HEAV08-03 · Lesson 3 · 15 clock hours · lab

The Loading Cycle: Crowd, Lift, Carry, and Dump

Objective. Students will execute a complete wheel loader production cycle—approach, crowd into material, lift to carry height, travel to dump point, and dump into a designated target—achieving a bucket fill factor of 90% or greater with fewer than two spills per session.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

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The Loading Cycle: Crowd, Lift, Carry, and Dump

A wheel loader's productivity is measured in complete loading cycles. Every cycle has four phases: crowd, lift, carry, and dump. Mastering each phase—and linking them smoothly—is the core skill of loader operation. Your target is a bucket fill factor of 90 % or greater on the great majority of your passes, with almost no material lost in travel.

Pre-Cycle Safety Checks

Before you turn a key, walk the area. Identify the stockpile boundaries, confirm no workers or bystanders are inside the swing radius, and check for overhead lines or low structures near the dump point. Put on all required PPE: hard hat, safety glasses, high-visibility vest, steel-toed boots, and hearing protection. Fasten your seat belt as soon as you mount—every time. Keep the cab door closed during travel so you are protected if the machine tips. Never allow riders on the machine.

Verify that the bucket pins and cutting edge are secure, hydraulic fluid level is correct, and tires are inflated to the manufacturer's specification. Report any defects before operating.

Phase 1 — Crowd (Approach and Penetration)

The crowd phase drives the bucket into the material pile to fill it. The technique that produces the best fill factor on loose materials such as sand or gravel is the J-approach combined with an angled attack.

J-approach: Instead of driving straight at the pile and stopping, you arc toward it in a shallow J-shaped path. This lets the machine arrive at the pile with some momentum while keeping the bucket edge parallel to the material face.

Angled attack: Approach the pile at roughly a 15- to 20-degree angle to one side. This causes material to roll into the bucket from both the face and the side rather than pushing a wall of material forward and losing it around the edges.

As the cutting edge enters the pile, apply forward ground drive and simultaneously roll the bucket curl (tilt) slightly forward—keeping the cutting edge flat or just slightly pitched down—to slice cleanly into the material. Use full engine RPM to maintain crowd force. Once penetration stops and the bucket is loaded, immediately tilt back (curl) to retain material, then begin the lift.

Phase 2 — Lift (Loading Position)

Once the bucket is curled back and full, raise the boom to carry height—approximately 12 to 18 inches off the ground. Do not raise the bucket higher than necessary for ground clearance; high carry height raises the center of gravity and reduces stability, especially on grades. Moving with the bucket at full height wastes time and fuel and is a tip-over hazard.

Verify the tilt-back indicator or feel the hydraulic stop that confirms the bucket is fully curled. A properly loaded bucket should show material level with or just slightly above the cutting edge lip—this is the visual cue for approximately 100 % fill. A bucket showing material clearly below the lip is under-filled.

Phase 3 — Carry (Travel to Dump Point)

Travel with the bucket at carry height, not at full lift. Drive at a controlled speed appropriate to ground conditions—reduce speed over rough terrain to prevent spilling. Look ahead and pick the smoothest line between the stockpile and the dump point. Sudden braking or sharp turns at speed will cause material to slosh out of an open-top bucket, creating a spill and a slip hazard for anyone walking the site.

Keep your eyes up and scan for pedestrians, other equipment, and ground obstacles. Sound your horn at blind intersections. Never travel with the bucket raised to dump height—this is both a stability and a visibility hazard.

Phase 4 — Dump

Position the machine at the dump point—aligned with the target boundary or over the truck body opening. Raise the boom to the required dump height and slowly roll the bucket forward (dump curl) to release material in a controlled stream. Control the rate of curl to direct material into the target; too fast a curl throws material and reduces accuracy.

For dumping into a truck body, approach from the rear or side as the site layout allows, keeping the truck in view at all times. Never raise the bucket over the cab of the truck. After dumping, curl back immediately to the carry position before lowering the boom and reversing away from the dump point.

Return and Reset

After dumping, lower the boom to carry height, curl back, and drive back toward the stockpile. Use the return path to re-plan your next approach angle. A tight, efficient return route reduces total cycle time and improves production.

Cycle Time and Fill Factor

Cycle time is measured from the start of one crowd to the start of the next. Shorter cycle times with high fill factors equal maximum production. Visual fill factor assessment: a full bucket (approx. 100 %) shows material flush with the top of the bucket sides. A 90 % fill shows material slightly below the lip but filling the bucket to near capacity. Consistently under-filled buckets waste machine time; overfilled buckets cause spills and can damage tires or the machine frame from overloading.

Key Safety Reminders

Key terms9

Loading cycleThe complete sequence of one loader production pass: crowd into material, lift to carry height, travel to the dump point, dump the load, and return to the stockpile.
CrowdThe phase in which the loader drives forward to force the bucket cutting edge into the material pile, using ground drive force and bucket angle to fill the bucket.
J-approachA curved approach path to the stockpile that allows the machine to arrive with momentum while positioning the bucket edge parallel to the pile face for better penetration.
Carry heightThe boom height used during travel between the stockpile and dump point—typically 12 to 18 inches above ground—that provides ground clearance while keeping the center of gravity low.
Bucket fill factorA measure of how completely a bucket is loaded, expressed as a percentage of struck capacity; a 90 % or greater fill factor is the target for efficient production.
Tilt-back (curl back)The hydraulic movement that rotates the bucket rearward to retain material after penetration; used immediately after crowding to lock the load in before lifting.
Dump curlThe forward rotation of the bucket to release material at the dump point; controlling the speed of dump curl directs material into the target accurately.
Angled attackAn approach to the pile at a slight angle (roughly 15–20 degrees off center) that causes material to flow into the bucket from the face and side simultaneously, improving fill factor.
Cycle timeThe elapsed time from the beginning of one crowd phase to the beginning of the next; shorter cycle times combined with high fill factors maximize loader production.

Worked examples4

1. A stockpile job requires moving 450 cubic yards of sand. The loader bucket has a struck capacity of 3 cubic yards and you are consistently achieving a 90 % fill factor. How many complete loading cycles are needed to move all the material?
  1. Step 1 — Find the actual volume moved per cycle: 3 cu yd × 0.90 = 2.7 cu yd per cycle.
  2. Step 2 — Divide the total volume by the volume per cycle: 450 ÷ 2.7 = 166.67.
  3. Step 3 — Round up to the next whole cycle because a partial cycle still requires a full pass: 167 cycles.
Answer: 167 complete loading cycles are required.
2. Your stopwatch shows that your last 5 loading cycles took 38 seconds, 41 seconds, 37 seconds, 40 seconds, and 39 seconds. What is your average cycle time?
  1. Step 1 — Add all cycle times: 38 + 41 + 37 + 40 + 39 = 195 seconds.
  2. Step 2 — Divide by the number of cycles: 195 ÷ 5 = 39 seconds.
  3. Step 3 — State the result clearly.
Answer: Your average cycle time is 39 seconds.
3. Using the 39-second average cycle time above, how many complete cycles can you perform in a 60-minute work period, assuming no delays?
  1. Step 1 — Convert 60 minutes to seconds: 60 × 60 = 3,600 seconds.
  2. Step 2 — Divide total seconds by seconds per cycle: 3,600 ÷ 39 = 92.3.
  3. Step 3 — Round down to the nearest whole cycle (you cannot complete a partial cycle in the time): 92 cycles.
Answer: 92 complete cycles in a 60-minute period with no delays.
4. During your 15-cycle assessment session you achieved a 90 % or greater fill factor on 13 cycles. What percentage of your cycles met the fill-factor target?
  1. Step 1 — Divide the number of passing cycles by total cycles: 13 ÷ 15 = 0.8667.
  2. Step 2 — Multiply by 100 to express as a percentage: 0.8667 × 100 = 86.67 %.
  3. Step 3 — Compare to the passing standard: the competency check requires at least 12 of 15 cycles (80 %) to meet fill-factor criterion; 86.67 % exceeds that standard.
Answer: 86.67 % of cycles met the fill-factor target, which exceeds the minimum passing requirement of 12 out of 15 cycles.

The math in this lesson2

Learners apply a 90% fill factor to a 3 cubic yard bucket to count passes for 450 cubic yards.
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Brush up in the math halls at newSchoolWorks.com:
In class: Instructor demo at a prepared loose-material stockpile (sand or gravel): demonstrate the J-approach, angled attack, crowd pressure application, tilt-back for full bucket, carry position travel, controlled dump into a windrow target, and return; students observe and take notes on a provided observation form. · Supervised repetition block—each student completes a minimum of 15 full cycles into a dump truck silhouette target (marked area on ground); instructor evaluates approach angle, bucket fill factor (visually assessed as near-level full), carry height, dump accuracy, and total cycle time, recording each cycle on a tally sheet. · Peer review and self-assessment: students review video footage (tablet-mounted camera on the machine) of their own cycles to identify one technique improvement; each student writes a one-paragraph correction plan that the instructor approves.
Materials: Wheel loader; prepared stockpile of sand or 3/4-inch gravel (minimum 50 cubic yards); dump truck silhouette target or retired truck body; tablet with video recording capability; cycle-time stopwatch; NCCER Heavy Equipment Level 2 loader production module; bucket fill-factor reference chart; PPE as above
Check: Over 15 observed cycles, student achieves a visual bucket fill factor of 90% or greater on at least 12 cycles, records fewer than 2 material spills during travel, and dumps within the target boundary at least 11 of 15 times; instructor tally sheet must show these counts to pass.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Heavy Equipment - Loader Operation
1. What is the primary purpose of using a J-approach when attacking a loose-material stockpile?
NCCER Heavy Equipment - Loader Operation
2. During the carry phase, why should the bucket be kept at carry height (approximately 12–18 inches) rather than at full lift height?
NCCER Heavy Equipment - Loader Production
3. A loader bucket has a struck capacity of 4 cubic yards. If the operator consistently achieves a 90 % fill factor, how many cubic yards of material are moved per cycle?
NCCER Heavy Equipment - Loader Operation
4. Which action immediately follows a successful crowd penetration and before the lift phase?
OSHA 10 - Construction Safety / Struck-By Hazards
5. What is the correct direction to approach a haul truck when dumping into the truck body with a wheel loader?
NCCER Heavy Equipment - Performance Assessment
6. During the 15-cycle assessment, a student records 11 cycles with a 90 %+ fill factor, 1 spill, and 11 of 15 dumps within the target boundary. Does the student pass the competency check?
OSHA 10 - Construction Safety / Equipment Operation
7. Which PPE item is specifically required by safety rules before the wheel loader begins to move, regardless of trip distance?
NCCER Heavy Equipment - Safe Operation / Stability
8. An operator notices the machine feels unstable while traveling with a loaded bucket. What is the correct immediate response?
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