If I recall correctly, aircraft equipped with INS could not fly published STARs because the INS was not RNAV compliant (excluding more modern INS units like the Litton LTN-92), so how were arrivals into airports flown with the non-RNAV compliant INS?

VOR/DME or other ground-based navaids. It was done that way for decades, still is in many planes.

The STAR (or SID, or IAP) will say what kind of navigation performance capability is required to fly it. If your avionics can't tell you where you are with the precision necessary to fly the procedure, you can't fly that procedure. Pick another way to get yourself where you want to go. The airport probably has a bunch of different instrument arrivals published.

LORAN equipped aircraft could fly certain RNAV STARs prior to GPS as well. But there are plenty of published arrivals and departures that can be flown strictly by VOR navigation - even without DME at times.

LongHaulFTW wrote:

how were arrivals into airports flown with the non-RNAV compliant INS?

I assume it is "how were INS arrivals..."?

Simple answer - were not.

There are requirements for STAR procedures. And stated on STAR approach plates and/or airport description. Unable? Not using these.

You can use any other (there are still some VOR based, even if limited nowadays), or ask for vectors (again - if available).

There are many options, INS based STAR is just one of the options.

Cheers,
Adam

LongHaulFTW wrote:

If I recall correctly, aircraft equipped with INS could not fly published STARs because the INS was not RNAV compliant (excluding more modern INS units like the Litton LTN-92), so how were arrivals into airports flown with the non-RNAV compliant INS?

l

Aircraft equipped with an INS/IRS could fly RNAV SIDS and STARs, however they needed some form of RNAV computer onboard like a FMS/FMC. The RNAV computer would take the INS/IRS position along with VOR, DME/DME, LORAN to automatically update its position.

The first of these would have been the AINS-70 on the DC-10 https://collinsaerospacemuseum.org/coll ... viewer.php (page 9 Aug 71)

Early A320s for example came about before GPS was available, and they could fly RNAV in the terminal area and enroute via DME/DME/IRU updates. There were standards called basic RNAV (B-RNAV) and precision RNAV P-RNAV.

GNSS allows for performance based monitoring (PBN), this is where the aircraft monitors and alerts the crew when the aircraft position is outside its prescribed navigation tolerance for the phase of flight.

gloom wrote:

You can use any other (there are still some VOR based, even if limited nowadays), or ask for vectors (again - if available).

I remember when the Houston Metroplex airspace project began the FAA HQ folks who kicked it off were very strong willed on keeping at least one conventional STAR from each of the four cornerposts for conventional NAV aircraft into the Houston Terminal Area all the while focusing on RNAV Arrivals and Optimized Profile Descents (OPD). I believe that was the mandate for most other Metroplex programs as well.

So yes, there are plenty of ground based NAVAID STAR procedures still in place.

IAHFLYR wrote:

So yes, there are plenty of ground based NAVAID STAR procedures still in place.

Agree. Still, one of the reasons to put INS procedures in place is gaining some extra capacity. That's what they're for. From capacity planning perspective, "it's not what you asked for". And I've seen people being asked to reconsider and perhaps use INS instead. Just wonder how much is that the case around the world, now that even Cessna (at least modern/upgraded one) is usually able to fly INS.

Cheers,
Adam

gloom wrote:

IAHFLYR wrote:

So yes, there are plenty of ground based NAVAID STAR procedures still in place.

Agree. Still, one of the reasons to put INS procedures in place is gaining some extra capacity. That's what they're for. From capacity planning perspective, "it's not what you asked for". And I've seen people being asked to reconsider and perhaps use INS instead. Just wonder how much is that the case around the world, now that even Cessna (at least modern/upgraded one) is usually able to fly INS.

Cheers,
Adam

It’s properly termed RNAV, or at higher precision RNP procedures. INS in inertial nabigation system which was the primary RNAV in jets. Now, it’s an IRS, inertial reference system and acts as a sensor for the FMS.

GalaxyFlyer wrote:

It’s properly termed RNAV, or at higher precision RNP procedures. INS in inertial nabigation system which was the primary RNAV in jets. Now, it’s an IRS, inertial reference system and acts as a sensor for the FMS.

Not really, RNAV is area navigation, there is no requirement for onboard performance monitoring and alerting, there is RNAV 10, 5, 2, 1. RNP is Performance-Based Navigation, where there must be onboard performance monitoring and alerting. There is RNP 4, 2, 1 0.3, 0.1, RNP AR etc.

RNAV 1 is not the same as RNP 1, both will keep you within 1 nm 95% of the time, RNP 1 would guarantee a containment of within 2 nm 99.999% of the time. You would generally find RNAV 1 used in a radar environment where ATC provides the navigational performance monitoring, outside radar coverage RNP 1 would be used as the aircraft is then able to monitor its navigational performance and alert the crew if required, it has a containment around the route. RNAV 1 (or 2) SIDS and STARs can be flown without GPS, DME/DME, DME/DME/IRS is fine.

Understand all that which why I posted “at higher precision RNP procedures”. Maybe an FAA/ICAO terminology difference. There are no “INS” STARs is the point. I do manage OpsSpecs for 3 international bizjets.

GalaxyFlyer wrote:

RNP procedures

Yup, I wa thinking RNP, yet used INS. Thanks for correction.

Cheers,
Adam

RNAV is a term thst has more and more been used generically in the US for generally GPS based procedures, regardless of the root word. The term RNP has generally been reserved for RNP-AR procedures and only recently have charts reflected that GPS based approaches that can be performed - often to greater precision by non airliners - by anyone with an IFR GPS are RNP procedures.

There is nothing called an INS procedure.

GalaxyFlyer wrote:

Understand all that which why I posted “at higher precision RNP procedures”. Maybe an FAA/ICAO terminology difference. There are no “INS” STARs is the point. I do manage OpsSpecs for 3 international bizjets.

All RNAV STARS in the US are RNAV 1, there is no requirement for GNSS at all to fly these or the RNAV airways, these are also RNAV 1. Refer to AC 90-100A for the equipment required to fly RNAV 1.

“RNAV STAR.

1. All public RNAV STARs are RNAV1. These procedures require system performance currently met by GPS or DME/DME/IRU RNAV systems that satisfy the criteria discussed in AC 90-100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations. RNAV1 procedures require the aircraft's total system error remain bounded by +1 NM for 95% of the total flight time.”

From https://tfmlearning.faa.gov/publication ... m0504.html

zeke wrote:

GalaxyFlyer wrote:

Understand all that which why I posted “at higher precision RNP procedures”. Maybe an FAA/ICAO terminology difference. There are no “INS” STARs is the point. I do manage OpsSpecs for 3 international bizjets.

All RNAV STARS in the US are RNAV 1, there is no requirement for GNSS at all to fly these or the RNAV airways, these are also RNAV 1. Refer to AC 90-100A for the equipment required to fly RNAV 1.

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

N1120A wrote:

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

I sure remember being part of the design team when the Houston Class B was redesigned back in the early 2000's, and the T Routes developed. It was a learning experience for all at that time with the requirements and not met with much enthusiasm from the GA folks as was expected since equipage didn't seem to be very high back then.

IAHFLYR wrote:

N1120A wrote:

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

I sure remember being part of the design team when the Houston Class B was redesigned back in the early 2000's, and the T Routes developed. It was a learning experience for all at that time with the requirements and not met with much enthusiasm from the GA folks as was expected since equipage didn't seem to be very high back then.

The biggest issue I see is sometimes ATC seems to forget T Routes exist - at least with ZLA and ZOA. The cross country and training GA fleet has steadily adopted GPS and I'd venture to guess that the vast majority of hours and NM flown are by GPS equipped aircraft.

N1120A wrote:

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

This is incorrect, T and Q airways are RNAV 2 except for those that are RNAV 1. GPS is not required to fly RNAV 1 or 2.

“Area Navigation (RNAV) Routes
Published RNAV routes, including Q-Routes and T-Routes, can be flight planned for use by aircraft with RNAV capability, subject to any limitations or requirements noted on en route charts, in applicable Advisory Circulars, or by NOTAM. RNAV routes are depicted in blue on aeronautical charts and are identified by the letter “Q” or “T” followed by the airway number (for example, Q-13, T-205). Published RNAV routes are RNAV-2 except when specifically charted as RNAV-1. These routes require system performance currently met by GPS, GPS/WAAS, or DME/DME/IRU RNAV systems that satisfy the criteria discussed in AC 90-100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations.”

From https://www.faa.gov/air_traffic/publica ... n_3.3.html

zeke wrote:

N1120A wrote:

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

This is incorrect, T and Q airways are RNAV 2 except for those that are RNAV 1. GPS is not required to fly RNAV 1 or 2.

“Area Navigation (RNAV) Routes
Published RNAV routes, including Q-Routes and T-Routes, can be flight planned for use by aircraft with RNAV capability, subject to any limitations or requirements noted on en route charts, in applicable Advisory Circulars, or by NOTAM. RNAV routes are depicted in blue on aeronautical charts and are identified by the letter “Q” or “T” followed by the airway number (for example, Q-13, T-205). Published RNAV routes are RNAV-2 except when specifically charted as RNAV-1. These routes require system performance currently met by GPS, GPS/WAAS, or DME/DME/IRU RNAV systems that satisfy the criteria discussed in AC 90-100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations.”

From https://www.faa.gov/air_traffic/publica ... n_3.3.html

You are incorrect.

https://www.faa.gov/air_traffic/publica ... n_3.3.html

"Q-routes are available for use by RNAV equipped aircraft between 18,000 feet MSL and FL 450 inclusive. Q-routes are depicted on En Route High Altitude Charts.
NOTE-

Aircraft in Alaska may only operate on GNSS Q-routes with GPS (TSO-C129 (as revised) or TSO-C196 (as revised)) equipment while the aircraft remains in Air Traffic Control (ATC) radar surveillance or with GPS/WAAS which does not require ATC radar surveillance.

T-routes are available for use by GPS or GPS/WAAS equipped aircraft from 1,200 feet above the surface (or in some instances higher) up to but not including 18,000 feet MSL. T-routes are depicted on En Route Low Altitude Charts."

N1120A wrote:

zeke wrote:

N1120A wrote:

In the US, Q Routes only require RNAV 1, which can be met by DME/DME/INS systems or GPS, but T routes additionally require GPS (to an RNAV 1 or better standard)or GPS/WAAS (which meets at least an RNAV 0.3 standard BTW).

This is incorrect, T and Q airways are RNAV 2 except for those that are RNAV 1. GPS is not required to fly RNAV 1 or 2.

“Area Navigation (RNAV) Routes
Published RNAV routes, including Q-Routes and T-Routes, can be flight planned for use by aircraft with RNAV capability, subject to any limitations or requirements noted on en route charts, in applicable Advisory Circulars, or by NOTAM. RNAV routes are depicted in blue on aeronautical charts and are identified by the letter “Q” or “T” followed by the airway number (for example, Q-13, T-205). Published RNAV routes are RNAV-2 except when specifically charted as RNAV-1. These routes require system performance currently met by GPS, GPS/WAAS, or DME/DME/IRU RNAV systems that satisfy the criteria discussed in AC 90-100A, U.S. Terminal and En Route Area Navigation (RNAV) Operations.”

From https://www.faa.gov/air_traffic/publica ... n_3.3.html

You are incorrect.

https://www.faa.gov/air_traffic/publica ... n_3.3.html

"Q-routes are available for use by RNAV equipped aircraft between 18,000 feet MSL and FL 450 inclusive. Q-routes are depicted on En Route High Altitude Charts.
NOTE-

Aircraft in Alaska may only operate on GNSS Q-routes with GPS (TSO-C129 (as revised) or TSO-C196 (as revised)) equipment while the aircraft remains in Air Traffic Control (ATC) radar surveillance or with GPS/WAAS which does not require ATC radar surveillance.

T-routes are available for use by GPS or GPS/WAAS equipped aircraft from 1,200 feet above the surface (or in some instances higher) up to but not including 18,000 feet MSL. T-routes are depicted on En Route Low Altitude Charts."

Try reading that again, and AC 90-100A. It is perfectly legal for RNAV aircraft to operate on T and Q routes without GPS. The reason for the altitudes listed has to do with rated coverage of aids and radar coverage. The reason for the Alaska reference is for rated coverage of ground based aids and radar coverage. I am mentioned earlier in this thread, the difference between RNAV and RNP is the onboard performance monitoring and reporting, for RNAV 1&2 ATC can provide that function through radar coverage. That is not possible all across Alaska, hence the variation.