Feathered
13th Oct 2017, 16:00
ATC data link messages that are delayed for many hours or even a day can be hazardous to flight.
Two incidents were reported involving CPDLC (Controller–pilot data link communications) messages that have led to the Iridium satellite service being banned for ATC use in several FIRs.
Oakland, Auckland, New York, Anchorage have issued NOTAMS prohibiting the use of Iridium service for CPLDC/ATC messages in their respective FIRs.
An Alaska Airlines flight in September received a CLIMB message intended for the previous flight and executed the climb. On the previous flight, the CMU had not delivered the message when it was intended.
A Hawaiian Airlines flight also received an ATC instruction data link message about 23 hours after it was sent, also intended for an earlier flight. The crew did not execute the instruction after confirming via voice.
Iridium is investigating and plans to fix the issue at some point. On Thursday 12 October, New York Oceanic also issued a NOTAM banning Iridium service for CPDLC messages. ADS-C is okay to use.
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A0622/17 NOTAMN Q) PAZA/QXXXX////000/999/ A) PAZA B) 1710102230 C) 1711102231 EST E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI THE ANCHORAGE OCEANIC, DOMESTIC AND ARCTIC FLIGHT INFORMATION REGIONS. FLIGHT CREWS CAN LOGON TO PAZN OR PAZA, AS APPROPRIATE, TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH ANCHORAGE ARTCC MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSTION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED. F) SFC G) UNL
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A4271/17 NOTAMR A4254/17 Q) KZAK/QXXXX////// A) KZAK B) 1710102214 C) 1712312359 E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI OAKLAND OCEANIC AIFSPACE. FLIGHT CREWS CAN LOGON KZAK TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH KZAK MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSITION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED.
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B4985/17 NOTAMN Q) NZZO/QCDLT/IV/BO /E /000/999/4348S16336W999 A) NZZO B) 1710082156 C) 1801082100 EST E) USE OF CPDLC (DATALINK) VIA IRIDIUM SATCOM IS PROHIBITED WI NZZO FIR. COMMUNICATION WI NZZO FIR IS TO BE VIA HF RDO ON THE APPROPRIATE SP6 FREQ. OPERATORS USING IRIDIUM SATCOM MAY CONTINUE TO USE ADS-C FOR POSITION REPORTING WI NZZO FIR. HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED
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A4271/17 NOTAMR A4254/17 Q) KZAK/QXXXX////// A) KZAK B) 1710102214 C) 1712312359 E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI OAKLAND OCEANIC AIFSPACE. FLIGHT CREWS CAN LOGON KZAK TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH KZAK MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSITION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED.
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On Sep 12th, an Alaskan Airlines flight had a failure of their CMU (Comms Management Unit) that caused the Iridium connection to stop working. An ATC message was sent to the aircraft but not delivered. On the next flight, the CMU power was reset and corrected the issue, and the pending message was delivered. The CMU did not recognise the message as being old, and so it was presented to the Flight Crew as a control instruction. FSB understands that this aircraft took the climb instruction and executed the level change, climbing 1000 feet.
Another flight, operated by Hawaiian out of Oakland, had a similar problem. This aircraft had both Iridium and Inmarsat on board, and during the flight switched over to Inmarsat as the provider. An ATC message was routed via Iridium, but didn’t reach the aircraft before the switch. Some 23 hours later, on the next flight, Iridium was activated again and again the ATC message presented as a “live” instruction. On this occasion, the crew queried the instruction and did not climb.
The problem in simple terms is that if ATC sends a CPDLC message like “Climb FL370“, which is obviously only valid for “right now”, but another crew gets the message hours later, then you have a very high risk of the new crew accepting that and climbing.
Additional Information http://flightservicebureau.org/iridium-fault/
Two incidents were reported involving CPDLC (Controller–pilot data link communications) messages that have led to the Iridium satellite service being banned for ATC use in several FIRs.
Oakland, Auckland, New York, Anchorage have issued NOTAMS prohibiting the use of Iridium service for CPLDC/ATC messages in their respective FIRs.
An Alaska Airlines flight in September received a CLIMB message intended for the previous flight and executed the climb. On the previous flight, the CMU had not delivered the message when it was intended.
A Hawaiian Airlines flight also received an ATC instruction data link message about 23 hours after it was sent, also intended for an earlier flight. The crew did not execute the instruction after confirming via voice.
Iridium is investigating and plans to fix the issue at some point. On Thursday 12 October, New York Oceanic also issued a NOTAM banning Iridium service for CPDLC messages. ADS-C is okay to use.
----
A0622/17 NOTAMN Q) PAZA/QXXXX////000/999/ A) PAZA B) 1710102230 C) 1711102231 EST E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI THE ANCHORAGE OCEANIC, DOMESTIC AND ARCTIC FLIGHT INFORMATION REGIONS. FLIGHT CREWS CAN LOGON TO PAZN OR PAZA, AS APPROPRIATE, TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH ANCHORAGE ARTCC MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSTION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED. F) SFC G) UNL
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A4271/17 NOTAMR A4254/17 Q) KZAK/QXXXX////// A) KZAK B) 1710102214 C) 1712312359 E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI OAKLAND OCEANIC AIFSPACE. FLIGHT CREWS CAN LOGON KZAK TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH KZAK MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSITION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED.
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B4985/17 NOTAMN Q) NZZO/QCDLT/IV/BO /E /000/999/4348S16336W999 A) NZZO B) 1710082156 C) 1801082100 EST E) USE OF CPDLC (DATALINK) VIA IRIDIUM SATCOM IS PROHIBITED WI NZZO FIR. COMMUNICATION WI NZZO FIR IS TO BE VIA HF RDO ON THE APPROPRIATE SP6 FREQ. OPERATORS USING IRIDIUM SATCOM MAY CONTINUE TO USE ADS-C FOR POSITION REPORTING WI NZZO FIR. HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED
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A4271/17 NOTAMR A4254/17 Q) KZAK/QXXXX////// A) KZAK B) 1710102214 C) 1712312359 E) FOR ACFT EQUIPPED WITH IRIDIUM SATCOM, USE OF CPDLC IS PROHIBITED WI OAKLAND OCEANIC AIFSPACE. FLIGHT CREWS CAN LOGON KZAK TO ALLOW THE USE OF ADS-C FOR POSITION REPORTING. COMMUNICATION WITH KZAK MUST BE VIA HF; CPDLC IS NOT AUTHORIZED. IF USING ADS-C POSITION REPORTING, HF VOICE POSITION REPORTS ARE NOT REQUIRED UNLESS SPECIFICALLY REQUESTED.
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On Sep 12th, an Alaskan Airlines flight had a failure of their CMU (Comms Management Unit) that caused the Iridium connection to stop working. An ATC message was sent to the aircraft but not delivered. On the next flight, the CMU power was reset and corrected the issue, and the pending message was delivered. The CMU did not recognise the message as being old, and so it was presented to the Flight Crew as a control instruction. FSB understands that this aircraft took the climb instruction and executed the level change, climbing 1000 feet.
Another flight, operated by Hawaiian out of Oakland, had a similar problem. This aircraft had both Iridium and Inmarsat on board, and during the flight switched over to Inmarsat as the provider. An ATC message was routed via Iridium, but didn’t reach the aircraft before the switch. Some 23 hours later, on the next flight, Iridium was activated again and again the ATC message presented as a “live” instruction. On this occasion, the crew queried the instruction and did not climb.
The problem in simple terms is that if ATC sends a CPDLC message like “Climb FL370“, which is obviously only valid for “right now”, but another crew gets the message hours later, then you have a very high risk of the new crew accepting that and climbing.
Additional Information http://flightservicebureau.org/iridium-fault/