· ICAO24 c81624· last seen Jul 2026

ZK-WFG is a Schleicher ASK 21. SkyMeter has tracked 72 flights totalling 32 hours of airtime via ADS-B. The most frequent segment is NZOI to NZTG. Service window in our records spans 392 days. Of those flights, 4 (5.6%) 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
72
all time
FLOWN HOURS
32
tracked time
📍
AIRPORTS VISITED
5
unique
📡
CALLSIGNS
1
7 routes
📅
SERVICE PERIOD
6/14/2025 → 7/12/2026
first → last
INCIDENT RATE
5.6%
4 flagged

Top routes

By flight count

4
8
4
2
1

Flight numbers

Most-flown by this airframe

1

Aircraft specifications

Schleicher ASK 21

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

Recent flights

Newest 36 operations of ZK-WFG

36
7/12/2026
22m
No alerts
6/13/2026
25m
No alerts
6/13/2026
18m
No alerts
6/13/2026
23m
No alerts
6/12/2026
26m
No alerts
5/3/2026
20m
△ Low approach-stability score
5/3/2026
20m
△ Low approach-stability score
5/3/2026
27m
No alerts
5/3/2026
27m
No alerts
5/3/2026
28m
No alerts
5/3/2026
28m
No alerts
3/7/2026
22m
No alerts
2/20/2026
18m
No alerts
2/20/2026
33m
No alerts
2/14/2026
27m
No alerts
2/14/2026
42m
No alerts
12/27/2025
30m
No alerts
12/27/2025
53m
No alerts
12/25/2025
10m
No alerts
12/25/2025
29m
No alerts
12/25/2025
29m
No alerts
12/20/2025
18m
No alerts
11/29/2025
23m
No alerts
11/8/2025
20m
No alerts
11/8/2025
39m
No alerts
9/27/2025
23m
No alerts
9/27/2025
9m
No alerts
9/26/2025
34m
No alerts
8/13/2025
16m
No alerts
8/12/2025
58m
No alerts
7/5/2025
15m
No alerts
7/5/2025
42m
No alerts
6/14/2025
46m
No alerts
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