Demo school. A sample flight school with four aircraft and two years of invented flights and bills (September 2024–August 2026). Sign in to see your own school's numbers.
N4521K flew 48% of the fleet's hours, and the others are due within days of it, so they could all be down at once.
Ideas schools in this spot often explore
Bringing one inspection forward a few days so the aircraft aren't down at the same time.
Whether the shop can take two aircraft in the same week, and how long each would take.
Which bookings fall in those weeks and could move to other aircraft.
Ideas, not recommendations. Your situation may differ.
Show the numbers
N4521K's 100-hour (about Nov 5, 2026) falls within 14 days of N8123V's 100-hour (about Oct 27, 2026) and N744PS's 100-hour (about Oct 28, 2026) (projected). N4521K flew 48% of the fleet's hours from 2026-07-03 to 2026-09-30.
N4521K 100-hour: about Nov 5, 2026
Also due: N8123V 100-hour: about Oct 27, 2026
Also due: N744PS 100-hour: about Oct 28, 2026
N4521K share of fleet hours: 48%
N4521K 100-hour: about Nov 5, 2026
Also due: N8123V 100-hour: about Oct 27, 2026
Also due: N744PS 100-hour: about Oct 28, 2026
N4521K share of fleet hours: 48%
Facts from your data, not a diagnosis.
N4521K: 100-hour (about Nov 5, 2026); it flies about 46.4 tach hours a month, and flew 48% of the fleet's hours from 2026-07-03 to 2026-09-30. main factor
N4521K hours per month: 46.4 h/month
N4521K share of fleet hours: 48%
Also due within 14 days: N8123V's 100-hour (about Oct 27, 2026) and N744PS's 100-hour (about Oct 28, 2026). smaller factor
Other aircraft due in the same weeks: 2
est Includes estimated values: inferred bills, placeholder fixed costs or allocated fuel. Figures for cancellations, downtime and unbilled ground sessions are estimates by design.
Informational only, based on your data. Not financial, legal, or aviation-maintenance advice.
Utilization by month
Apr–Sep, by calendar month. Based on your weekly schedule.
Flights, newest first
Date
Kind
Hobbs start
Hobbs end
Tach start
Tach end
Source
0 total
Maintenance
Maintenance/hr (12-month)
$25/hr
Hourly (100-hour inspections, oil, other flying wear)
$22/hr
Calendar (annual and other date-driven items)
$238/month
Unscheduled repairs in this range
$0
Engine reserve per hour (overhaul cost ÷ TBO)
$21/hr
Maintenance booked in this range
$0
Per-hour and per-month figures cover 2025-10-01 to 2026-09-30 (995.1 Hobbs hours), so one month's annual or a month with few hours doesn't swing them. The operating break-even uses them too. Operating cost and margin stay as booked.
Coming up
Next 100-hour
About Nov 5, 2026 (at tach 6,427.9)
23% of the way
est
Next annual
Due by Dec 31, 2026
76% of the way
Overhaul
About April 2028
61% of the way
est
Reserve per hour
$21.00 needed
Dates marked est are estimates: the 100-hour from this aircraft's upcoming bookings and its last 90 days of hours (hover it for how), the overhaul projected at about 46.4 tach hours a month, month by month as it flew from 2025-10-01 to 2026-09-30, × 0.67 for its recent trend.
Maintenance downtime
No maintenance recorded in this range.
Downtime counted against utilization in this range: 0.0 h (times in America/Chicago).
Summary
Hours flown
Utilization
Based on your weekly schedule.
Revenue
Operating cost
Operating margin
Loan payments
After loan payments
Cash view: includes loan principal
Cost/hr
Cost/hr (12-month)
0.0
0.0%
$0
−$875est
−$875est
−$1,150est
−$2,025est
—
$94est
Operating cost by category
Fuel
$0
0%
Maintenance
$0
0%
Insurance
−$425est
49%
Hangar
−$450est
51%
Lease payment
$0
0%
Instructor pay
$0
0%
Other
$0
0%
Operating cost
−$875est
100%
Loan payments (after the operating margin, not in cost)
−$1,150est
est Includes estimated values: inferred bills, placeholder fixed costs or allocated fuel.
Bars are drawn against the largest category; striped bars include estimates. The percent is each category's share of the operating cost.
Fixed-cost placeholders (no bill booked that month, so the aircraft's monthly field is used): 2026-09 Insurance $4252026-09 Hangar $450
Loan-payment placeholders (no bill booked that month, so the aircraft's monthly field is used): 2026-09 Loan payment $1,150
By month
Month
Hours flown
Utilization
Based on your weekly schedule.
Revenue
Operating cost
Operating margin
After loan payments
Cash view: includes loan principal
September 2026
0.0
0.0%
$0
−$875est
−$875est
−$2,025est
Range total
0.0
0.0%
$0
−$875est
−$875est
−$2,025est
Cost per hour, month by month
Month
Hours
Fuel
Maintenance
Oct 2025
90.2
$67/hr
$24/hr
Nov 2025
61.1
$71/hr
$3/hr
Dec 2025
63.2
$46/hr
$45/hr
Jan 2026
56
$50/hr
$47/hr
Feb 2026
52.3
$69/hr
$4/hr
Mar 2026
92.9
$68/hr
$31/hr
Apr 2026
103.3
$58/hr
$19/hr
May 2026
111.1
$71/hr
$21/hr
Jun 2026
125.6
$51/hr
$18/hr
Jul 2026
124.1
$47/hr
$36/hr
Aug 2026
115.3
$54/hr
$24/hr
Sep 2026
0
—
—
Calendar maintenance (annual inspections and other dated items): 2024 (part) $3,086 · 2025 $2,862 · 2026 (part) $0
Maintenance per hour is lumpy month to month (an annual lands in one month); the 12-month rate above smooths it.