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Author Topic: Oceanic entry checks  (Read 317 times)

Will

  • Join date: May 2009
  • Location: Chicago
  • Posts: 2291
Oceanic entry checks
« on: Tue, 12 Oct 2021 04:00 »
Hi all, the default OFP in the PFPX flight planning software prints some blanks at the point of Oceanic Entry for the crew to fill out:

[  ] LR NAV ACCUR CHECK   CAPT_____  STBY _____   FO_____

[  ] RSVM ALTIMETER CHECK   CAPT_____  STBY _____   FO_____

[  ] COMPASSS HDG CHECK   CAPT_____  STBY _____   FO_____

[  ] HF CHECK

That's from a generic fictional OFP for an unspecified aircraft. I'm wondering what kind of checks (if any?) a real-world B747 crew might do prior to entering oceanic airspace.

For example, regarding "LR ACCUR CHECK," are we simply talking about errors on POS REF 2/4 (NG FMC) lines LSK2R-4R? If so, what minimum error is acceptable for oceanic (or Class II airspace) navigation? Or is something else supposed to be checked here?

Also, I know the OFP here is not written for a B747, but when we're talking about navigation accuracy, would be meant by "CAPT_____  STBY _____   FO_____?" For the 747, wouldn't it be more proper to say "IRS_____  GPS_____  RADIO_____" instead of capt, stby, and FO?

Also, for HF radios, how would you perform an "HF CHECK?" Just call ATC using the HF radios and see if they can hear? Or test SELCAL by sending a "do you copy?" message?

Thanks.
Will /Chicago /USA

Jeroen Hoppenbrouwers

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  • Hoppie designs avionics equipment for airliners.
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Re: Oceanic entry checks
« Reply #1 on: Tue, 12 Oct 2021 10:43 »
Don't know about the first, but HF:

* Pilots make call and ask for SELCAL check.
* This is not a call to ATC. ATC does not have HF capability (!). They call a commercial radio operator.
* Radio operator confirms the request. This now has confirmed two-way voice radio contact.
* Radio operator keys in the SELCAL from the flight plan.
* Pilots confirm the SELCAL chime goes off.
* Pilots make call and confirm everything ok.

If the aircraft has a SATCOM, they make a SATCOM call. And if they need both SATCOM and HF, they have two tests to perform. And with two dissimilar SATCOM and no HF, which is a future option that the industry pursues, still two.

If you have two HF radios (and no SATCOM), you don't need to make two test calls. The radios have the same SELCAL code anyway and share a lot of common equipment such as the antenna.

/-/


Unrelated freebie for those who get here:

https://twitter.com/lemonodor/status/1447692604653531136

John Wiseman (@lemonodor): "I think N300WQ was doing bathymetric LIDAR scans along the coast of Los Angeles last night. A couple nights before someone took this video of it doing the same thing in San Diego."

IefCooreman

  • Join date: May 2011
  • Posts: 264
Re: Oceanic entry checks
« Reply #2 on: Tue, 12 Oct 2021 20:19 »
Selcal checks are done with an operator that monitors multiple frequencies so you would have to add the frequency on which you are calling them. In general a call on a flight using CPDLC would go like this:

Aircraft: “Gander, Gander, (callsign), on 56.”
Operator: “(callsign), Gander, go-ahead.”
Aircraft: “Gander, (callsign), CPDLC, track_ (or NAT exit point if on random
route), request SELCAL check.”
Operator: “(callsign), Gander, voice position reports not required, here is your
SELCAL.”
Aircraft: “Gander, (callsign), SELCAL received."

ATC gives the HF frequencies the operators are working on. Once we try to establish contact, the frequencies are usually abbreviated to 2 digits (two numbers give the operator enough info on which frequency he has to reply).

No experience in major airlines, but in smaller airlines flightplans are pretty "generic" as well. It boils down to specific aircraft equipment to know what you're supposed to do with it. Even though we were flying the 777, our flightplans were the same as the 747 and I never saw this L/R check. I believe LR nav accuracy check was a pre FMC requirement with separate INS systems where post flight also overall IRS drift had to be noted. But someone should confirm this. And a compass... no comment :-).

We had the RVSM check which was useless to us as in normal ops both pilots get to see the same data anyway. Left/right navigation doesn't really exist as we had ADIRU and SAARU. There was a time limit in case of GPS failure and outside of navaid coverage, but that "non-normal" situation we never experienced honestly and it is more QRH than flightplan related. We did do a waypoint plotting procedure on charts prior entry and 10 mins after waypoint crossing to make sure we didn't mess up the routing lol

Mariano

  • Join date: May 2009
  • Posts: 777
Re: Oceanic entry checks
« Reply #3 on: Tue, 12 Oct 2021 22:32 »
Will, this is from our 747 fleet:

“IRS/FMS Navigation Accuracy Check

Accomplish this IRS/FMS navigation accuracy check prior to entry into airspace requiring Class II navigation.
• Verify ANP is less than RNP for the intended airspace. Note: The “UNABLE RNP” EICAS message will not be displayed if  ANP is less than RNP.

Recording of IRS Positions

Record the IRS positions for relative accuracy while still within FMC radio updating range. This recording may help determine which IRU should be used for navigation in the event of a dual FMC failure.
• Select POS REF (Legacy FMC - page 3/3, NG FMC - page 4/4) and select BRG/DIST.
• Record the nautical mile error for each IRS on the MFP or plotting chart.

It is helpful to push the POS switch and select 10 NM or less range on the EFIS control panel. Observe the IRS position, represented by the three stars on the ND.

Notwithstanding the above, ongoing verification of the FMC and IRS positions should be made as needed.”

Best regards,

Mariano

Will

  • Join date: May 2009
  • Location: Chicago
  • Posts: 2291
Re: Oceanic entry checks
« Reply #4 on: Wed, 13 Oct 2021 03:47 »
Okay, that's helpful. Thanks!
Will /Chicago /USA

Will

  • Join date: May 2009
  • Location: Chicago
  • Posts: 2291
Re: Oceanic entry checks
« Reply #5 on: Thu, 14 Oct 2021 02:10 »
I updated the OFP template in PFPX. It used to be this:



-------------------------------- OCEANIC ENTRY ---------------------------------

[ ] LR NAV ACCUR CHECK     AT __:__Z    CAPT _______   STBY _______   FO _______   
[ ] RVSM ALTIMETER CHECK   AT __:__Z    CAPT _______   STBY _______   FO _______   
[ ] COMPASS HDG CHECK      AT __:__Z    CAPT _______   STBY _______   FO _______   
[ ] HF CHECK               AT __:__Z    SIGNATURE ______________________

--------------------------------------------------------------------------------


And now it is this:


-------------------------------- OCEANIC ENTRY ---------------------------------

[ ] LR NAVIGATION CHECK        IRS L: _____  IRS R: _____  IRS C: _____ 
[ ] REQUIRED NAV PERFORMANCE   RNP:   _____  ANP:   _____ 
[ ] ALTIMETER CHECK            CAPT:  _____  STBY:  _____  F/O:   _____   
[ ] HEADING CHECK              CAPT:  _____  STBY:  _____  F/O:   _____   
[ ] HF COM/SELCAL CHECK                 
                               TIME: ______   SIGNATURE: ______________

--------------------------------------------------------------------------------



I wonder if that looks more relevant and usable?

Although for heading, maybe it should be FMC L, FMC R, FMC C, and COMP?
« Last edit: Thu, 14 Oct 2021 02:30 by Will »
Will /Chicago /USA