Taipei, Oct. 16 (CNA) Taiwan's Civil Aeronautics Administration (CAA) on Friday disclosed a full transcript of the communications between Taiwanese and Hong Kong air traffic controllers, rebutting the latter's claim that one of its planes had voluntarily abandoned its flight plan, and insisted that it was the Hong Kong side that had denied permission for the plane to proceed to the disputed Dongsha Island claimed by both sides.

The incident happened on Thursday when a civilian aircraft from Taiwan chartered by the military was advised by Hong Kong air traffic controllers not to enter the airspace over a group of islands in the South China Sea because "dangerous activities" were in progress in the area, according to the CAA.

The Dongsha Islands, administered by Taiwan but also claimed by China, are located about 310 kilometers southeast of Hong Kong and are within its Flight Information Region (FIR).

It has been standard practice for Taiwanese air traffic controllers to inform their Hong Kong counterparts whenever a plane in the Taipei FIR is about to enter the Hong Kong FIR and is about 20-30 nautical miles away.

On the day of the incident, Hong Kong contacted Taipei's air traffic controller when the Taiwanese plane was 50-60 nautical miles away from the Hong Kong-administered FIR, the CAA said.

The UNI Air ATR2-600 aircraft was trying to transport coast guard officers, who were returning from a break, and marine national park personnel to Dongsha. Around 250 Taiwanese coastguard officers are stationed on Dongsha atoll, also known as Pratas Islands.

The Taipei air traffic controller that day tried to ask the Hong Kong side if the denial of passage was due to ongoing military exercises, but was only told that no further information could be given, according to the transcript released Friday.

However, in one of the responses, the air traffic controller revealed that Hong Kong simply could not allow the Taiwanese plane into the area.

"Affirmative, so Hong Kong cannot accept this aircraft. Can you talk to your military?" the Hong Kong air traffic controller responded.

Asked by the Taipei air traffic controller if any notice had been issued in advance about the supposed danger in the area, the Hong Kong air traffic controller said "no." Normally, notice is given 48 hours in advance for activities such as military drills, according to experts.

Ealier on Friday, Hong Kong's Civil Aviation Department told CNA that it received a CAA notice of the UNI Air flight's planned entry into the Hong Kong FIR and reminded Taiwan's air traffic controllers that the aircraft must stay above the minimum safe altitude.

Then Taiwan's air traffic control center told it to cancel the request for the UNI Air flight to enter the FIR, the Hong Kong department said, adding that it followed existing protocols in handling the situation.

According to the transcript, the Hong Kong air traffic controller had indicated the area below an altitude of 26,000 feet was the danger area, and that the area above that altitude was not dangerous, but that type of passenger aircraft is not equipped to fly above 26,000 feet.

The UNI Air flight was eventually forced to return to southern Taiwan's Kaohsiung City.

Below is the transcript of communication between Hong Kong ACC and Taipei ACC

0936:31

HK: taipei this is hong kong supervisor

TACC: hello area control center

HK: taipei this is hongkong supervisor lima delta

TACC: yeah go ahead

HK: regarding the glory traffic glory nine zero five one

TACC: nine zero five one

HK: yes

TACC: go ahead

HK: transfer (unacknowledgeabl) transfer supposed to be overhead the kapli at time zero one five seven at flight level one six zero

TACC: eh he

HK: ok and eh for your info for your information we have got a danger area west of kapli actually its very close to kapli over looking traffic and the safty altitude is flight level two six zero or above

TACC: dangee? what is that about dangee?

TACC: dangee area danger area is there a danger area? i am not aware of it

HK: because thats within hong kong just west of (unacknowledgeable)

TACC: oh is it about military exercise?

HK: i cannot tell you any more about that but there is a danger area over there

TACC: ok so flight level two six zero or above is the danger area altitude?

HK: no the safety altitude is flight level two six zero or above

TACC: oh ok but the glory nine zero five one is departing or entering?

HK: its eh entering hong kong

TACC: but there is a danger area below flight level two six zero?

HK: affirmative so hong kong cannot accept this aircraft can you talk to your military?

TACC: ok i will do that

HK: ok

TACC: eh can i have the time of the danger area?

HK: the danger area is eh now on until further notice

TACC: is there a notam? (notice to airmen)

HK: eh no

HK: because of (unacknowledgeable) you have to tell the

TACC: so you won’t accept glory nine zero five one?

HK: affirmative the altitude is not safe for danger after hong kong at this level

TACC: ok roger that can you let me know eh if there is further information when can glory go to romeo charlie lima mike

HK: ok hong kong is not able to advise right now we’ll let you know