Back Beam ILS

[Threethirteen]

I can vaguely remember something about opposite-polarised Localiser Lobes but am a bit sketchy about the exact technical details.

Can someone please refresh my memory and remind me why we don't do this type of approach in the UK?

[forget]

http://www.pprune.org/forums/archive/index.php/t-44597.html

[Pugilistic Animus]

The US is the king of the [as we call it] backcourse, that link to the archived thread was very intriguing. not having much to add other than most ILS aprch's in the US have a backcourse aprch also certified in order to increase the utility of the terminal airspace and departing traffic can also utilize a backcourse as part of a DP

I've heard of a mythical creature that combines a backcourse with g/s but I've never seen such a system operational.

We also have other varieties of LOC-only Localizer Type Directional aids (LDA) and Simplified directional facilities (SDF) ocasionally with g/s [so they say] useable backcourse and there circling minima for these aprch's are frequently published and the minima decrease in the following order loc-lda-sdf because angular offset from the rwy that may be up to 30 deg. off the aprch end of the rwy.

recently, with the introduction of simultaneous off-set parallel precision radar monitored [prm] {SOIA} approches, the localizer's utility will go even further in expanding airport capacity the FAA produces a mandatory video that details the execution of these special types of SAAR [special aircraft and aircrew req'd] approaches i'll try to find the link to the video on then FAA's web site
http://www.tc.faa.gov/acb300/330_video.asp

[forget]

How far did the US get with PRM? I seem to remember it wasn't exactly welcomed by pilots/airlines. How did they solve the VHF Comm issue when a controller called for an 'Escape'. I have an ALPA demonstration video, somewhere, of a FedEx DC-10 crew (simulator) sucking hard when told to 'Escape' by ducking under the Glide Slope on approach. :hmm:

[Pugilistic Animus]

I believe it's currently operational at DFW and SFO. I know the FAA is hailed as a 'tombstone agency and such' but they've addressed the issues you bring up with the 'breakout manuever' suggesting that it be hand flown i've put a small excerpt fom the aim ch5 sorry about it's length

Besides system requirements as identified in subpara a (http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/Chap5/aim0504.html#dj4j11e1mweb) above all pilots must have completed special training before accepting a clearance to conduct ILS/PRM or LDA/PRM Simultaneous Close Parallel Approaches.
1. Pilot Training Requirement. Pilots must complete special pilot training, as outlined below, before accepting a clearance for a simultaneous close parallel ILS/PRM or LDA/PRM approach.
(a) For operations under 14 CFR Parts 121, 129, and 135 pilots must comply with FAA approved company training as identified in their Operations Specifications. Training, at a minimum, must require pilots to view the FAA video "ILS PRM AND SOIA APPROACHES: INFORMATION FOR AIR CARRIER PILOTS." Refer to http://www.faa.gov (http://www.faa.gov/) for additional information and to view or download the video.
(b) For operations under Part 91:
(1) Pilots operating transport category aircraft must be familiar with PRM operations as contained in this section of the Aeronautical Information Manual (AIM). In addition, pilots operating transport category aircraft must view the FAA video "ILS PRM AND SOIA APPROACHES: INFORMATION FOR AIR CARRIER PILOTS." Refer to http://www.faa.gov (http://www.faa.gov/) for additional information and to view or download the video.

MAP
The point along the LDA where the course separation with the adjacent ILS reaches 3,000 feet. The altitude of the glide slope at that point determines the approach minimum descent altitude and is where the NTZ terminates. Maneuvering inside the MAP is done in visual conditions.
Angle
Angle formed at the intersection of the extended LDA runway centerline and a line drawn between the LDA MAP and the SAP. The size of the angle is determined by the FAA SOIA computer design program, and is dependent on whether Heavy aircraft use the LDA and the spacing between the runways.
Visibility
Distance from MAP to runway threshold in statute miles (light credit applies).
Procedure
LDA aircraft must see the runway landing environment and, if less than standard radar separation exists between the aircraft on the adjacent ILS course, the LDA aircraft must visually acquire the ILS aircraft and report it in sight to ATC prior to the LDA MAP.
CC
Clear Clouds.

(2) Pilots not operating transport category aircraft must be familiar with PRM and SOIA operations as contained in this section of the AIM. The FAA strongly recommends that pilots not involved in transport category aircraft operations view the FAA video, "ILS PRM AND SOIA APPROACHES: INFORMATION FOR GENERAL AVIATION PILOTS." Refer to http://www.faa.gov (http://www.faa.gov/) for additional information and to view or download the video.
2. ATC Directed Breakout. An ATC directed "breakout" is defined as a vector off the ILS or LDA approach course in response to another aircraft penetrating the NTZ, the 2,000 foot wide area located equidistance between the two approach courses that is monitored by the PRM monitor controllers.
3. Dual Communications. The aircraft flying the ILS/PRM or LDA/PRM approach must have the capability of enabling the pilot/s to listen to two communications frequencies simultaneously.
c. Radar Monitoring. Simultaneous close parallel ILS/PRM and LDA/PRM approaches require that final monitor controllers utilize the PRM system to ensure prescribed separation standards are met. Procedures and communications phraseology are also described in paragraph 5-4-15 (http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/Chap5/aim0504.html#7Q8140ROBE), Simultaneous Parallel ILS/MLS Approaches (Independent). A minimum of 3 miles radar separation or 1,000 feet vertical separation will be provided during the turn-on to close parallel final approach courses. To ensure separation is maintained, and in order to avoid an imminent situation during simultaneous close parallel ILS/PRM or SOIA ILS/PRM and LDA/PRM approaches, pilots must immediately comply with PRM monitor controller instructions. In the event of a missed approach, radar monitoring is provided to one-half mile beyond the most distant of the two runway departure ends for ILS/RPM approaches. In SOIA, PRM radar monitoring terminates at the LDA MAP. Final monitor controllers will not notify pilots when radar monitoring is terminated.
d. Attention All Users Page (AAUP). ILS/PRM and LDA/PRM approach charts have an AAUP associated with them that must be referred to in preparation for conducting the approach. This page contains the following instructions that must be followed if the pilot is unable to accept an ILS/PRM or LDA/PRM approach.
1. At airports that conduct PRM operations, (ILS/PRM or, in the case of airports where SOIAs are conducted, ILS/PRM and LDA/PRM approaches) pilots not qualified to except PRM approaches must contact the FAA Command Center prior to departure (1-800-333-4286) to obtain an arrival reservation (see FAA Advisory Circular 90-98, Simultaneous Closely Spaced Parallel Operations at Airports Using Precision Runway Monitor (PRM) Systems). Arriving flights that are unable to participate in ILS/PRM or LDA/PRM approaches and have not received an arrival reservation are subject to diversion to another airport or delays. Pilots en route to a PRM airport designated as an alternate, unable to reach their filed destination, and who are not qualified to participate in ILS/PRM or LDA/PRM approaches must advise ATC as soon as practical that they are unable to participate. Pilots who are qualified to participate but experience an en route equipment failure that would preclude participation in PRM approaches should notify ATC as soon as practical.
2. The AAUP covers the following operational topics:
(a) ATIS. When the ATIS broadcast advises ILS/PRM approaches are in progress (or ILS PRM and LDA PRM approaches in the case of SOIA), pilots should brief to fly the ILS/PRM or LDA/PRM approach. If later advised to expect the ILS or LDA approach (should one be published), the ILS/PRM or LDA/PRM chart may be used after completing the following briefing items:
(1) Minimums and missed approach procedures are unchanged.
(2) PRM Monitor frequency no longer required.
(3) ATC may assign a lower altitude for glide slope intercept.
NOTE-
In the case of the LDA/PRM approach, this briefing procedure only applies if an LDA approach is also published.
In the case of the SOIA ILS/PRM and LDA/PRM procedure, the AAUP describes the weather conditions in which simultaneous approaches are authorized:
Simultaneous approach weather minimums are X,XXX feet (ceiling), x miles (visibility).
(b) Dual VHF Communications Required. To avoid blocked transmissions, each runway will have two frequencies, a primary and a monitor frequency. The tower controller will transmit on both frequencies. The monitor controller's transmissions, if needed, will override both frequencies. Pilots will ONLY transmit on the tower controller's frequency, but will listen to both frequencies. Begin to monitor the PRM monitor controller when instructed by ATC to contact the tower. The volume levels should be set about the same on both radios so that the pilots will be able to hear transmissions on at least one frequency if the other is blocked. Site specific procedures take precedence over the general information presented in this paragraph. Refer to the AAUP for applicable procedures at specific airports.
(c) Breakouts. Breakouts differ from other types of abandoned approaches in that they can happen anywhere and unexpectedly. Pilots directed by ATC to break off an approach must assume that an aircraft is blundering toward them and a breakout must be initiated immediately.
(1) Hand-fly breakouts. All breakouts are to be hand-flown to ensure the maneuver is accomplished in the shortest amount of time.
(2) ATC Directed "Breakouts." ATC directed breakouts will consist of a turn and a climb or descent. Pilots must always initiate the breakout in response to an air traffic controller's instruction. Controllers will give a descending breakout only when there are no other reasonable options available, but in no case will the descent be below the minimum vectoring altitude (MVA) which provides at least 1,000 feet required obstruction clearance. The AAUP provides the MVA in the final approach segment as X,XXX feet at (Name) Airport.
NOTE-
"TRAFFIC ALERT." If an aircraft enters the "NO TRANSGRESSION ZONE" (NTZ), the controller will breakout the threatened aircraft on the adjacent approach. The phraseology for the breakout will be:
PHRASEOLOGY-
TRAFFIC ALERT, (aircraft call sign) TURN (left/right) IMMEDIATELY, HEADING (degrees), CLIMB/ DESCEND AND MAINTAIN (altitude).
(d) ILS/PRM Navigation. The pilot may find crossing altitudes along the final approach course. The pilot is advised that descending on the ILS glideslope ensures complying with any charted crossing restrictions.
SOIA AAUP differences from ILS PRM AAUP
(e) ILS/PRM LDA Traffic (only published on ILS/PRM AAUP when the ILS PRM approach is used in conjunctions with an LDA/PRM approach to the adjacent runway). To provide better situational awareness, and because traffic on the LDA may be visible on the ILS aircraft's TCAS, pilots are reminded of the fact that aircraft will be maneuvering behind them to align with the adjacent runway. While conducting the ILS/PRM approach to Runway XXX, other aircraft may be conducting the offset LDA/PRM approach to Runway XXX. These aircraft will approach from the (left/right)-rear and will realign with runway XXX after making visual contact with the ILS traffic. Under normal circumstances these aircraft will not pass the ILS traffic.
SOIA LDA/PRM AAUP Items. The AAUP for the SOIA LDA/PRM approach contains most information found on ILS/PRM AAUPs. It replaces certain information as seen below and provides pilots with the procedures to be used in the visual segment of the LDA/PRM approach, from the time the ILS aircraft is visually acquired until landing.
(f) SOIA LDA/PRM Navigation (replaces ILS/PRM (d) (http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/Chap5/aim0504.html#8z4j1166mweb) and (e) (http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/Chap5/aim0504.html#Sz4j11132mweb) above). The pilot may find crossing altitudes along the final approach course. The pilot is advised that descending on the LDA glideslope ensures complying with any charted crossing restrictions. Remain on the LDA course until passing XXXXX (LDA MAP name) intersection prior to maneuvering to align with the centerline of runway XXX.
(g) SOIA (Name) Airport Visual Segment (replaces ILS/PRM (e) (http://www.faa.gov/airports_airtraffic/air_traffic/publications/ATpubs/AIM/Chap5/aim0504.html#Sz4j11132mweb) above). Pilot procedures for navigating beyond the LDA MAP are spelled out. If ATC advises that there is traffic on the adjacent ILS, pilots are authorized to continue past the LDA MAP to align with runway centerline when:
(1) the ILS traffic is in sight and is expected to remain in sight,
(2) ATC has been advised that "traffic is in sight."
(3) the runway environment is in sight.
Otherwise, a missed approach must be executed. Between the LDA MAP and the runway threshold, pilots of the LDA aircraft are responsible for separating themselves visually from traffic on the ILS approach, which means

[Pugilistic Animus]

you may also find these interesting

http://www.myairplane.com/databases/approach/pdfs/06039CONI36L.PDF
http://www.myairplane.com/databases/approach/pdfs/06039CONIY18L.PDF
http://www.myairplane.com/databases/approach/pdfs/06039CONI13R.PDF
http://www.myairplane.com/databases/approach/pdfs/00375LDAPRM28R.PDF
http://www.myairplane.com/databases/approach/pdfs/00375LDAD28R.PDF
http://www.myairplane.com/databases/approach/pdfs/00375LDAPRM28R_C.PDF

the first two are actually 'converging ils' that DO NOT use PRM, but the last 3 are excellent examples, also check out MSP

[forget]

That's what you'd call a detailed response. Pug Ani, you may want to edit your diagram resolution so that it doesn't spoil the post by running a few yards to the right.

Pugilistic Animus; maybe my Latin master was right - but is 'fighting spirit' close enough? :)

[Pugilistic Animus]

Forget, affirmative, fighting soul/spirit

sorry about the gigantic diagram i've tried to shrink it but wasn't sure how to do as you suggest, so It was deleted, but thanks for pointing that out a little embarassing.

I normally wouldn't paste such a huge excerpt and the video is more interesting anyhow, they use MSP as their example I was fast about posting the first three plates for dfw those are converging ILS not requiring PRM---sorry

[BizJetJock]

To answer the original question, the reason we don't do backcourse approaches in the UK is because the type of localiser antenna used at UK airfields don't produce a useable back signal. I believe they were deliberately designed this way to try and minimise interference.

[eckhard]

The Hatfield ILS (Aah, de Havilland!) on 24 used to provide a very useful backbeam which lined up rather well with Leavesden's runway 24. Not that we ever used it of course :E