aidc transaction delay

CIVIL AVIATION BUREAU OF JAPANCIVIL AVIATION BUREAU OF JAPANMinistry of Land Infrastructure and Transport

Japan Civil Aviation Bureau

IPACG/40IPACG/40September, 2014September, 2014

Significant delaySignificant delay in AIDC transaction in AIDC transaction

Systems Development, Evaluation Systems Development, Evaluation and Contingency management Centerand Contingency management Center

(SDECC)(SDECC)


Systems Development, Evaluation and Contingency management Center

Switchover of AIDC line At IPACG/39, JCAB reported as follows:

• AIDC line between FAA and JCAB was switched over from leased line to AMHS on 9 July 2013.

• AIDC transaction time via AMHS was generally within 20 seconds, which was longer than via leased line, this was acceptable for AIDC operation.

2



Increase of AIDC transaction timeouts JCAB received information from FAA that the number of AIDC

transaction timeouts was on the increase from January 2014.

On investigation, the following fact was found:

• Consecutive AIDC transaction timeouts occurred in a short time period;

• This time period came out irregularly by the frequency of once or twice a month.

• In this time period, it takes several minutes until FIMS (system handling ATS messages in JCAB) transmits an AIDC message to AIDC server after receiving it from AMHS.

3



Number of timeouts (February 2014)

0

10

20

30

40

50

60

70

80

1-Fe

b

2-Fe

b

3-Fe

b

4-Fe

b

5-Fe

b

6-Fe

b

7-Fe

b

8-Fe

b

9-Fe

b

10-F

eb

11-F

eb

12-F

eb

13-F

eb

14-F

eb

15-F

eb

16-F

eb

17-F

eb

18-F

eb

19-F

eb

20-F

eb

21-F

eb

22-F

eb

23-F

eb

24-F

eb

25-F

eb

26-F

eb

27-F

eb

28-F

eb

RJJJ-PAZN over 180 sec


RJJJ-KZOA over 180 sec


RJJJ-PAZN/KZOA over 180 sec

AIDC transaction time between RJJJ and PAZN/KZOA (February 2014)

4



0

10

20

30

40

50

60

70

80

1-M

ar2-

Mar

3-M

ar4-

Mar

5-M

ar6-

Mar

7-M

ar8-

Mar

9-M

ar10

-Mar

11-M

ar12

-Mar

13-M

ar14

-Mar

15-M

ar16

-Mar

17-M

ar18

-Mar

19-M

ar20

-Mar

21-M

ar22

-Mar

23-M

ar24

-Mar

25-M

ar26

-Mar

27-M

ar28

-Mar

29-M

ar30

-Mar

31-M

ar

RJJJ-PAZN over 180 secRJJJ-PAZN over 60 secRJJJ-KZOA over 180 secRJJJ-KZOA over 60 secRJJJ-PAZN/KZOA over 180 sec

AIDC transaction time between RJJJ and PAZN/KZOA (March 2014)

Number of timeouts (March 2014)

AIDC transaction timeouts occurred 77 times.AIDC

transaction timeouts occurred 23 times.

5



Number of timeouts (April 2014)

0

10

20

30

40

50

60

70

80

1-Ap

r2-

Apr

3-Ap

r4-

Apr

5-Ap

r6-

Apr

7-Ap

r8-

Apr

9-Ap

r10

-Apr

11-A

pr12

-Apr

13-A

pr14

-Apr

15-A

pr16

-Apr

17-A

pr18

-Apr

19-A

pr20

-Apr

21-A

pr22

-Apr

23-A

pr24

-Apr

25-A

pr26

-Apr

27-A

pr28

-Apr

29-A

pr30

-Apr

RJJJ-PAZN over 180 secRJJJ-PAZN over 60 secRJJJ-KZOA over 180 secRJJJ-KZOA over 60 secRJJJ-PAZN/KZOA over 180 sec

AIDC transaction time between RJJJ and PAZN/KZOA (April 2014)

AIDC transaction timeouts occurred 20 times.

6



Number of timeouts (May 2014)

0

10

20

30

40

50

60

70

80

1-M

ay2-

May

3-M

ay4-

May

5-M

ay6-

May

7-M

ay8-

May

9-M

ay10

-May

11-M

ay12

-May

13-M

ay14

-May

15-M

ay16

-May

17-M

ay18

-May

19-M

ay20

-May

21-M

ay22

-May

23-M

ay24

-May

25-M

ay26

-May

27-M

ay28

-May

29-M

ay30

-May

31-M

ay






AIDC transaction time between RJJJ and PAZN/KZOA (May 2014)

AIDC transaction timeouts occurred 39 times.AIDC

transaction timeouts occurred 19 times.

7



Number of timeouts (June 2014)

8

0

10

20

30

40

50

60

70

80

1-Ju

n

2-Ju

n

3-Ju

n

4-Ju

n

5-Ju

n

6-Ju

n

7-Ju

n

8-Ju

n

9-Ju

n

10-Ju

n

11-Ju

n

12-Ju

n

13-Ju

n

14-Ju

n

15-Ju

n

16-Ju

n

17-Ju

n

18-Ju

n

19-Ju

n

20-Ju

n

21-Ju

n

22-Ju

n

23-Ju

n

24-Ju

n

25-Ju

n

26-Ju

n

27-Ju

n

28-Ju

n

29-Ju

n

30-Ju

n

PAZN RJJJ-PAZN over 180 sec

PAZN RJJJ-PAZN over 60 sec

KZCE RJJJ-KZOA over 180 sec

KZCE RJJJ-KZOA over 60 sec

PAZN RJJJ-PAZN/KZOA over 180 sec

AIDC transaction time between RJJJ and PAZN/KZOA (June 2014)




Number of timeouts (July 2014)

9

0

10

20

30

40

50

60

70

80

90

1-Ja

n2-

Jan

3-Ja

n4-

Jan

5-Ja

n6-

Jan

7-Ja

n8-

Jan

9-Ja

n10

-Jan

11-Ja

n12

-Jan

13-Ja

n14

-Jan

15-Ja

n16

-Jan

17-Ja

n18

-Jan

19-Ja

n20

-Jan

21-Ja

n22

-Jan

23-Ja

n24

-Jan

25-Ja

n26

-Jan

27-Ja

n28

-Jan

29-Ja

n30

-Jan

31-Ja

n






AIDC transaction time between RJJJ and PAZN/KZOA (July 2014)




Number of timeouts (August 2014)

10

0

10

20

30

40

50

60

70

80

1-Au

g2-

Aug

3-Au

g4-

Aug

5-Au

g6-

Aug

7-Au

g8-

Aug

9-Au

g10

-Aug

11-A

ug12

-Aug

13-A

ug14

-Aug

15-A

ug16

-Aug

17-A

ug18

-Aug

19-A

ug20

-Aug

21-A

ug22

-Aug

23-A

ug24

-Aug

25-A

ug26

-Aug

27-A

ug28

-Aug

29-A

ug30

-Aug

31-A

ug






AIDC transaction time between RJJJ and PAZN/KZOA (August 2014)



Cause of AIDC transaction timeouts A transmission delay occurred in a data transmitting

from FIMS to AIDC server, when a data congestion at FIMS occurred.

FIMS can process up to 100 ATS messages (include AIDC messages) which received from AMHS and AFTN lines, per minute.

When significant number of timeouts occurred, FIMS was receiving over 250 ATS messages per minute.

11



Cause of AIDC transaction timeouts These messages contained the ATS messages not

passing through RJJJ in a usual condition. It can be inferred that when AFTN alternate sub-

network was established due to AFTN line trouble which had occurred somewhere in the world, ATS messages accumulated in AFTN network flowed into RJJJ.

12



RJJJ

Other ATSU

Cause of AIDC transaction delay

FIMS AMHSserver

AIDCserver

AFTNstation

AFTNstation

DELAY

A transmission delay will occur when FIMS receives over 100 ATS messages per minute from AMHS and AFTN.

AMHS link

AFTNstation

13



Alternate routing of AFTN line

14

RJJJKSLC

A

B E

C

D

Z AFTN station Ordinary routing Alternate routing AFTN line trouble



Countermeasures for this issue The measure to be taken for this problem is

under consideration in JCAB.

15

aidc transaction delay

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