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Garmin GNS430 & 530 versus 430W/530W (and approach coding)

JasonC wrote:

So with LPV in Europe you can’t tell the DH in the cockpit as you can’t know whether it has a 200 or 250 system minima. How idiotic.

Q.E.D.

ESTL

Anders wrote:

Great clarification NCYankee!

But a bit un-user friendly to have to dive into the FAS Data Block to know which system minima to apply.

LPV-200 approach at Budpest

RocketRoute link to the approach plate

My highlight of what to check do know if it is 250ft or 200ft.

It is obviously an LPV200 as the OCH on the 4% MACG LPV is below 200ft. Another classic messy European set of OCHs…

On reflection maybe not – apologies Anders. So with LPV in Europe you can’t tell the DH in the cockpit as you can’t know whether it has a 200 or 250 system minima. How idiotic.

Last Edited by JasonC at 31 Oct 14:35
EGTK Oxford

In the US, the VAL does not set the DH, the DH sets the VAL. A VAL of 35 meters is used for a DH between 200 and 249 feet.

KUZA, United States

Great clarification NCYankee!

But a bit un-user friendly to have to dive into the FAS Data Block to know which system minima to apply.

LPV-200 approach at Budpest

RocketRoute link to the approach plate

My highlight of what to check do know if it is 250ft or 200ft.

ESTL

HAL and VAL are not considered, they are set to match the requirements of the approach.

HAL and VAL values for various types of approach procedures:

LPV DH >= 250 feet, HAL is set to 40 meters and VAL is set to 50 meters
LPV DH < 250 feet, HAL is set to 40 meters and VAL is set to 35 meters
LP, HAL is set to 40 meters and VAL is not set, but if advisory vertical guidance is provided (+V), then VPL must not exceed 50 meters
LNAV/VNAV HAL and VAL are not set, but HPL must not exceed 556 Meters and VPL must not exceed 50 meters
LNAV HAL and VAL are not set, but HPL must not exceed 556 Meters and if advisory vertical guidance is provided (+V), VPL must not exceed 50 meters

In the US, there are two LPV specifications, LPV and LPV200. The main difference is that LPV only provides for a DH to 250 feet, while the LPV200 provides for a DH down to 200 feet and a visibility as low as 1/2 SM. In order for a runway to qualify for the lowest LPV200 DH and visibility, the runway must be at least 4200 feet long, have precision markings, approach lights, and a parallel taxiway. There must not be any obstacles in the 34 to 1 slope as well.

KUZA, United States

Should not the HAL and VAL value be considered, among a myriad of other parameters, when designing the approach and establishing the OCA(H) ?
In which case those values must satisfy LPV200 conditions in order to result in a OCH below 250 ft.
That is the only way I can get the rules to make sense.

Last Edited by huv at 31 Oct 13:12
huv
EKRK, Denmark

Jeppesen gets the FAS Data Block as part of the definition of the final approach definition. It includes fields for the HAL and VAL values. I also presume they get the DA in source data from the state. They certainly do from US TERPS.

KUZA, United States

Anders wrote:

What information does Jeppesen use when they calculate the DA?

It looks as if Jeppesen has done exactly as you and I would have. Compared the OCH and the system minima and used the higher value. Since I referred to Part-NCO in an earlier post, I have checked Part-CAT also, and confirmed that system minima is lowered to 200 ft for commercial ops flying LPV also, and the way DH is established is identical. So Jeppesen would not have the problem of differentiating between commercial and non-commercial ops.

With system minima being 250 ft at the time of Jeppesen publishing an approach, that would have been the minimum value for the approach before lowering system minima.

Whether system minima was actually lowered with the final introduction of the new OPS rules on August 25th this year, or it happened before, I do not know.

It would be interesting to know if any LPV approaches have been commissioned i EASA-land since August 25th, and which DH Jeppesen in that case have put on their plates.

Last Edited by huv at 31 Oct 13:01
huv
EKRK, Denmark

I’ve also wondered how a pilot in Europe is supposed to know whether a specific LPV approach was designed for LPV250 or LPV200.
What information does Jeppesen use when they calculate the DA?

One thing that I have heard that the EGNOS NOTAMs for LPV250 and LPV200 are different.

ESTL

NCYankee, the Eurocontrol document has the VAL = 50 m on page 5 and the system minimum of 200 ft on page 7. However, I suspect you are right. The document is obviously not a technical or authoritative paper, but only a presentation. But Part-NCO, which is the law for pilots, makes no mention of VAL or HAL. I think I will ask some of the gurus in PPLIR.

Last Edited by huv at 30 Oct 19:26
huv
EKRK, Denmark
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