ENR 5.3 OTHER ACTIVITIES OF A DANGEROUS NATURE

1 WEATHER BALLOONS

1.1 Balloons will be released for MET observation at:
  1. Upper Air Observatory (0120N 10353E), bearing 244° Mag and distance 1.5NM from southern end of Paya Lebar RWY 02; and
  2. Changi Met Station (0122N 10359E), bearing 014° Mag and distance 1.1NM from southern end of RWY 02L.
1.1.1 At Upper Air Observatory, balloons will be released daily at 2330UTC and 1040UTC plus or minus 30 minutes.

Rate of ascent of balloon: 320m per minute.
Maximum height of balloon: 110 000ft (33 500m).
Colour of balloon: uncoloured.
Diameter of balloon: 156m.

The balloon is attached with radiosonde equipment.
Weight of radiosonde equipment: 290g (with dry cell batteries attached).
Payload (radiosonde plus parachute): 330g.
Size of radiosonde equipment: (220 x 80 x 75)mm.

The balloon will burst 1.5 to 2 hours after release and radiosonde equipment will descend within 60NM radius.

1.1.2 At Upper Air Observatory, a balloon will be released between 0230UTC-0300UTC on the 2nd Thursday of every month.

Rate of ascent of balloon: 305m per minute.
Maximum height of balloon: 115 000ft (35 000m).
Colour of balloon: uncoloured.
Diameter of balloon: 202cm.

The balloon is attached with ozonesonde/radiosonde equipment and parachute.
Total weight of ozonesonde/radiosonde equipment: 950g.
Size of ozonesonde/radiosonde equipment: (19 x 19 x 25) cm.

The balloon will burst 1.5 to 2 hours after release.

1.1.3 At Changi Met Station, balloons will be released daily at 0530UTC and 1800UTC plus or minus 15 minutes.

Rate of ascent of balloon: 500ft (150m) per minute.
Maximum height of balloon: about 40 000ft (12 200m).
Colour of balloon: Red.
Diameter of balloon: 2.1ft (0.7m).

At night a small lantern lighted up with a candle is attached. The balloon will burst 1 to 1.5 hours after release.

Balloon release shall be delayed until cessation of precipitation e.g. showers or rain at the station (if any) until 0830UTC (for 0600UTC PILOT report) and 2030UTC (for 1800UTC PILOT report).

If condition persists beyond the above mentioned timings, there will be no PILOT balloon release.