This discussion is totally different in the US. There are almost four times the number of LPV than ILS procedures. An LPV can provide a Cat 1 capability to both towered and non-towered airports. The vast majority of IFR equipped piston aircraft are LPV capable. Business aircraft are for the most part LPV equipped. Of the 5000+ public use airports in the US, only 520 are towered. More than 2000+ public use airports have LPV and 1000+ are to a DH of 200 feet. So here it is part of the infrastructure. Only the smaller airports with runway lengths under 3500 feet are unlikely to have an LPV. LPV doesn’t require approach lighting to obtain a 200 foot DH. Most public use airports are open 24/7 and don’t have a landing fee. ILS installation costs are such that except at the major airports, that typically all runways do not have ILS and many have LPV on the ILS as well as other runways. LPV does not come with temperature limitations of Baro-VNAV. Vertical guidance can be used all the way to the runway and the GP will remain clear of obstacles, whereas LNAV or LP is restricted to use above the MDA because the procedures don’t guarantee obstacle clearance. GA pilots prefer flying an LPV over an ILS when the choice is available. LPV is much simpler to fly than ILS because all the navigation uses GPS whereas ILS requires changing the Nav Source to VLOC for the final approach segment and back again to GPS for the missed approach guidance. There is no need to tune the correct localizer frequency and identify it as being the proper one. Distances are displayed to the runway threshold and not to the location of the localizer/DME antenna off the far end of the departure runway. LPV does not have false GS. LPV is not affected by signal aberrations caused by traffic on or near the runway, by runway conditions such as snow, or terrain/obstacles that distort ILS signals. Maintenance for LPV is not an airport expense as it is for ILS. LPV has proven to be more reliable than ILS in terms of availability.
I also stumbled over the temperature limitation of LNAV/VNAV vs LPV. Here the limit is typically set to -15 degrees centigrade, that we seldom see in middle Germany. However it is possible to have these temperatures. And then LNAV/VNAV is not allowed.
By the way does anyone happen to know whether it relates to temperature on ground or OAT?
Yeager wrote:
So, you´re saying that a non-WAAS(SBAS) GPS aircraft installation do not provide/display Vertical Guidance that can be legally used down to LNAV/VNAV minima´s? I´m not convinced, but could I´m uncertain.
lt is not a question of legalities but of what the equipment can do. I don’t know of any non-SBAS boxes that provides advisory glidepaths.
EDIT (SORRY): A quick glance at some technical data discloses that you can indeed have non-WAAS(SBAS) GPS “boxes” and perform (3D) LNAV/VNAV approaches to applicable LNAV/VNAV minima, for as long as you have a barometric-VNAV system (which we do have on the more advanced jets (as well as SBAS of course). So, no, SBAS(WAAS) capable GPS “boxes” are NOT a requirement, as per se, to perform LNAV/VNAV approaches. SBAS capable GPS “boxes” is one way to allow for the Vertical Guidance for the LNAV/VNAV approach and ditto minima.
Sure, but I don’t think that any GA short of some bizjets/turboprops have Baro-LNAV so I didn’t see it as relevant. And these aircraft do have the equipment and systems redundancy to regularly operate down to 200 ft minima so you would want LPV capability,
I don’t know of any non-SBAS boxes that provides advisory glidepaths.
Since SBAS is not needed for +V with the latest boxes and latest firmware, that is probably because nobody has made any non-SBAS boxes for many years. +V is fairly recent.
The US owns the avionics business and LPV is mandatory there, as NCyankee says,
LPV does not come with temperature limitations
Assuming you are flying temperature corrected minima when required. Some airports/approaches have temperature limitations for GPSS in any event.
Airborne_Again wrote:
lt is not a question of legalities but of what the equipment can do. I don’t know of any non-SBAS boxes that provides advisory glidepaths.
If the onboard GPS installation is capable of baro-VNAV you do NOT need a WAAS(SBAS) capable GPS installation. I´m not very familiar with the various onboard GPS equipment available to the GA market. If you have capable GPS equipment installation, you can benefit (limited in my view) from lower minima, legally as well.
UdoR wrote:
By the way does anyone happen to know whether it relates to temperature on ground or OAT?
It is the temperature (OAT) on the ground at the landing airfield (or, under certain conditions, a remote airfield defined on the approach chart as the source of pressure/“altimeter setting” if conditions dictate the use of this remote airfields weather data).
RobertL18C wrote:
Assuming you are flying temperature corrected minima when required.
Correct. The LPV approach with the VGP can from an operational point of view be considered similar to a conventional ILS GP and referenced in the same way, with temperature corrections for altimeter cross check(s) (if available) and minima corrections to DA. Not to forget the temp corrections for missed approach altitude(s) and the MSA.
NCYankee wrote:
LPV doesn’t require approach lighting to obtain a 200 foot DH.
I was not aware that you could have LPV to 200ft (DH) without approach lightning. However, the visibility/RVR requirements would be increased accordingly and with NALS (No Approach Light System) available the minimum RVR is 1200 meters (in my OM-A).
For precision approaches (ILS or LPV) the vis/RVR was/is the only limiting factor in planning (destination airport), and when operationally executing the approach, with the ceiling (DH) not being a limiting factor. Destination Alternate airport for planning is (can be) different.
The LPV approaches are awesome and the future, I think even EASA has realized this.
France tends to be going the same way regarding the introduction of LPVs, as outlined by @NCYankee, minus the zero landing fees.
@Yeager I have been flying in and out of LFBH La Rochelle for many years now. I even had my aircraft based there for around 15 years. The debate of whether or not to have LPV equipment on board is a personal decision in the same way as whether you fly IFR or VFR.
Personally, I found the ability to fly the LPV to 09 at LFBH a great advantage during December 22 and Jan 23 when I was returning there on cold nights on multiple occasions. It often made the difference between coming home or spending an extra night in a hotel away from home.
That is why I wrote in my first comment that if you are equipping to fly IFR in France, I would advise you equip for LPV.
Yeager wrote:
If the onboard GPS installation is capable of baro-VNAV you do NOT need a WAAS(SBAS) capable GPS installation.
Obviously. Once again:
Airborne_Again wrote:
Sure, but I don’t think that any GA short of some bizjets/turboprops have Baro-LNAV so I didn’t see it as relevant [to this discussion].
gallois wrote:
if you are equipping to fly IFR in France, I would advise you equip for LPV.
I agree, The reason why France went this direction was to save cost on all the ILS calibrations required as the huge cost associated with that was pushed back on the AD operators. All the rest what NCYkee I fully agree, changing NAV sources for the final segment and then back to GPS for the missed causes a potential risk of lost mode awareness or at least adds up to the workload including interpretations of DME distances to…etc….
The reason why France went this direction was to save cost on all the ILS calibrations required . . .
I remember being in the Bistro at Calais when some official was trying to persuade the airport manager to have an LVP Approach:
“We can restore and maintain your ILS for an annual fee of €30,000 or create a RNAV LVP Approach for free.
A No Brainer . . .
