· ICAO24 c81588· last seen May 2026

ZK-OGX is a Schleicher ASK 21. SkyMeter has tracked 46 flights totalling 21 hours of airtime via ADS-B across 2 callsigns. The most frequent segment is NZES to NZHN. Service window in our records spans 337 days. Of those flights, 2 (4.3%) carry at least one detected incident: a go-around, unstable approach, stall warning, or runway excursion. The Schleicher ASK 21 has a maximum takeoff weight of 1,433 lb, light wake category.

About the Schleicher ASK 21

The Schleicher ASK 21 is a two-seat glider that has become the world's most widely used sailplane for training and recreational soaring since its introduction in 1979. Built by Alexander Schleicher GmbH in Poppenhausen, Germany, the ASK 21 revolutionized glider instruction with its forgiving handling characteristics, side-by-side seating, and exceptional durability, qualities that made it the standard training platform for gliding clubs across Europe and beyond. The aircraft's all-fiberglass construction and 17-meter wingspan deliver a best glide ratio of approximately 34:1, allowing student pilots to stay aloft for extended periods while learning thermal soaring techniques and cross-country navigation.

Unlike earlier training gliders with tandem seating, the ASK 21's side-by-side cockpit configuration improves instructor-student communication and makes it equally suitable for private owners seeking a rugged two-place sailplane. The type remains in production after more than four decades, with over 800 built, a testament to its enduring design. Its operating envelope spans from a minimum sink rate of about 2.1 feet per second at 46 knots to a never-exceed speed of 135 knots, with normal operations limited to 108 knots to preserve structural integrity during aerotow and thermaling flight.

SkyMeter has tracked flights across airframes and operators over routes, with the largest observed operator.

FLIGHTS
46
all time
FLOWN HOURS
21
tracked time
📍
AIRPORTS VISITED
11
unique
📡
CALLSIGNS
2
13 routes
📅
SERVICE PERIOD
06/14/2025 → 05/18/2026
first → last
INCIDENT RATE
4.3%
2 flagged

Top routes

By flight count

7
3
2
1
1
1
1

Flight numbers

Most-flown by this airframe

2

Aircraft specifications

Schleicher ASK 21

Engines
0
Vref (approach)
50 kt
MTOW
1,433 lb
Wake category
L

Recent flights

Newest 23 operations of ZK-OGX

23
05/18/2026
1h 9m
No alerts
05/18/2026
10m
No alerts
05/17/2026
39m
No alerts
05/14/2026
1h 2m
No alerts
04/25/2026
39m
No alerts
03/19/2026
22m
No alerts
02/21/2026
16m
No alerts
12/09/2025
21m
No alerts
12/07/2025
39m
No alerts
12/06/2025
20m
No alerts
11/25/2025
35m
No alerts
11/16/2025
15m
No alerts
11/05/2025
31m
No alerts
11/04/2025
19m
No alerts
09/20/2025
2m
No alerts
08/21/2025
1h 8m
No alerts
07/27/2025
13m
No alerts
07/07/2025
38m
No alerts
07/06/2025
22m
△ Low approach-stability score
07/06/2025
2m
No alerts
07/06/2025
3m
No alerts
06/15/2025
17m
No alerts
06/14/2025
25m
No alerts
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