What is a SRE approach
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Search Radar Equipment approach. Not many civvy fields do this now, more a military thing these days.
The deal is, ATC tell you which heading to fly, and what altitudes you should be at during the descent (crosschecked against distance to go) to remain on the "Glidepath".
Not as accurate as a PAR, hence classed as an airfield approach, rather than a runway approach, and can only be flown without visual reference to a minimum height above touchdown of about 450 - 500 ft.
The deal is, ATC tell you which heading to fly, and what altitudes you should be at during the descent (crosschecked against distance to go) to remain on the "Glidepath".
Not as accurate as a PAR, hence classed as an airfield approach, rather than a runway approach, and can only be flown without visual reference to a minimum height above touchdown of about 450 - 500 ft.
Instead of using a narrow radar beam directed up the approach path (PAR) the procedure uses the ordinary 360 degree surveillance radar in the tower. It is not as accurate hence the higher minimas for the approach. In the Military it is often done by the local controller using a radar repeater screen in the visual control room.
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As already stated by the chaps above SRE is the kit that gives you a SRA.
Think a less accurate ILS that talks to you rather than deflects needles; or a PAR with azimuth only.
Typically the controller will give you headings to maintain the centreline and height information to maintain the correct glide path E.G. G-XXXX turn left heading 272, passing 4 miles your altitude should be 650 Feet.
This continues until your minima where you will maintain a Minimum Descent Ht/Alt until you either get the references required to land or reach your MAP; where if you dont have references SOP is to poo your pants, look at the fuel guage and try again somewhere very close.
Think a less accurate ILS that talks to you rather than deflects needles; or a PAR with azimuth only.
Typically the controller will give you headings to maintain the centreline and height information to maintain the correct glide path E.G. G-XXXX turn left heading 272, passing 4 miles your altitude should be 650 Feet.
This continues until your minima where you will maintain a Minimum Descent Ht/Alt until you either get the references required to land or reach your MAP; where if you dont have references SOP is to poo your pants, look at the fuel guage and try again somewhere very close.
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Oops, I incorrectly called it "search radar equipment" rather than "surveillance radar equipment" but it is the same thing.
SRE Approach = SRA.
I vaguely recall that the military AIDU Red book (En route supplement, or was that the yellow book? - it's been quite a while) changed from using the term SRA, to SRE for a while and then I think it changed back again. Possibly around the time they went from QFE to QNH then QFE again?
However, Pooleys now call this type of approach an SRA and it IS still available at St Mawgan. Interestingly, irrespective of which runway is in use, the SRA inbound track is 304* in this case. The St Mawgan plate also gives "circle to land" minima for occasions where the wind favours another runway; as I said in my first post, it's an airfield approach, rather than a runway approach.
SRE Approach = SRA.
I vaguely recall that the military AIDU Red book (En route supplement, or was that the yellow book? - it's been quite a while) changed from using the term SRA, to SRE for a while and then I think it changed back again. Possibly around the time they went from QFE to QNH then QFE again?
However, Pooleys now call this type of approach an SRA and it IS still available at St Mawgan. Interestingly, irrespective of which runway is in use, the SRA inbound track is 304* in this case. The St Mawgan plate also gives "circle to land" minima for occasions where the wind favours another runway; as I said in my first post, it's an airfield approach, rather than a runway approach.
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Mmmmmm ...
Good fun ...????? remember years ago flying in the Uk (around Cranfield/Bedford Radar Area) and being asked by the tower/Radar guy if I would PLEASE do a "Homing and surveillance radar approach" PLEASE! .... 'cos he needed to control a certain number of them for HIS currency!
At home in Oz .. if I dared to ask for one for whatever reason ... the wall of paperwork was rediculous!
PS vaguely remember having to demonstrate one fo the issue of UKATPLH ??
such a long long long time ago
Good fun ...????? remember years ago flying in the Uk (around Cranfield/Bedford Radar Area) and being asked by the tower/Radar guy if I would PLEASE do a "Homing and surveillance radar approach" PLEASE! .... 'cos he needed to control a certain number of them for HIS currency!
At home in Oz .. if I dared to ask for one for whatever reason ... the wall of paperwork was rediculous!
PS vaguely remember having to demonstrate one fo the issue of UKATPLH ??
such a long long long time ago
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Ground based approaches such as SRAs and PARs aren't flown often at civvy airfields these days, although military trained pilots are (or were) very well versed in them as some mil aircraft didn't have ILS not long back.
A few years ago, at Kai Tak, a typhoon was going through the area and the eye of the storm had just passed. This meant the very strong wind sudden;y reversed in direction, causing a runway change. The first aircraft onto RW31 couldn't receive the ILS and carried out a missed approach.
ATC told the second aircraft that the ILS hadn't come on line and they were being vectored for a PAR approach instead. The crew asked for the message to be repeated twice then asked what a PAR was!
The controller said "Precision Approach Radar"!!
To my amazement - the pilot answered, in a nervous sounding voice: "We cannot do a PAR because we don't have that equipment fiitted!"
Eh? ATC had no option but to make them climb back into the stack until the ILS came on line!
A few years ago, at Kai Tak, a typhoon was going through the area and the eye of the storm had just passed. This meant the very strong wind sudden;y reversed in direction, causing a runway change. The first aircraft onto RW31 couldn't receive the ILS and carried out a missed approach.
ATC told the second aircraft that the ILS hadn't come on line and they were being vectored for a PAR approach instead. The crew asked for the message to be repeated twice then asked what a PAR was!
The controller said "Precision Approach Radar"!!
To my amazement - the pilot answered, in a nervous sounding voice: "We cannot do a PAR because we don't have that equipment fiitted!"
Eh? ATC had no option but to make them climb back into the stack until the ILS came on line!
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or a PAR with azimuth only.
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as some mil aircraft didn't have ILS not long back.
The RAF Eurofighters that visited Sola Air Show last year did not have ILS, don't know if that's true for all jets coming off the line at Warton.
(Btw, it's not a current fighter ac issue, it's a RAF issue)
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Yes, the SRA brings back memories. Most Civ airports in the UK used to do these back in the days when they only had ILS on one end of the runway. Back in those days they had a seperate more sensitive radar (the Decca 424 comes to mind) and the approach was conducted as a continuous talkdown to 0.5 miles from touchdown - guidance was given on heading to maintain the centreline with advisory height checks every half mile with a decision height typically of 300 feet or sometimes lower.
These days most UK Civ airports that are radar equiped publish SRA procedures but utilise the standard airport surveillance radar and the approach terminates at 2 miles with a correspondingly increased decision height. In reality, the procedure is only used in abnormal circumstances such as ILS unservicability.
There may still be the odd place in the UK where 0.5 mile SRA talkdown is available - Gloucester comes to mind, maybe Cambridge, not sure.
These days most UK Civ airports that are radar equiped publish SRA procedures but utilise the standard airport surveillance radar and the approach terminates at 2 miles with a correspondingly increased decision height. In reality, the procedure is only used in abnormal circumstances such as ILS unservicability.
There may still be the odd place in the UK where 0.5 mile SRA talkdown is available - Gloucester comes to mind, maybe Cambridge, not sure.
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Cambridge does still give an SRA to 0.5nms, at least it's still published in Jeppesen's Airways Manual.
after reading this thread, we flew an SRA today at Humberside so yes, they're still able to do them. I believe Radar controllers have to do so many before being signed off solo. LOL.
You'd have to check with atc'ers tho.
You'd have to check with atc'ers tho.
Years ago on a visit to Aerospatial at Marignane I looked around a brand new Puma that was going off to some Asian operator. It had the whole works, twin ILS, VOR and twin ADF. The HSI and AI was the same as the RAF had and it was merely a matter of plugging them in.
After years of stumbling around the UK VMC below cloud and having to land in the occasional field because we couldn’t see or climbing and taking your chances with a PAR at a Master Diversion I expressed the opinion to a senior staff officer of Air Support Command that we would be well advised to fit a similar kit to our squadron aircraft.
The cost was peanuts, about ₤6,000 per aircraft plus time to fit it.
I was grandly told, as he had bigger rings than I had so he knew much more about flying Pumas than I did, that it was totally unnecessary as in a war they would be switched off.
My contentions that I had joined the Air Force to ensure that there was not another war and that we were wasting time and money getting lost without proper equipment were totally ignored and eventually my argument was terminated by a fellow officer who led me away before I got court martialled.
I don’t know what they have now, but I hope it is better than a map, stopwatch and a wavy Decca map.
After years of stumbling around the UK VMC below cloud and having to land in the occasional field because we couldn’t see or climbing and taking your chances with a PAR at a Master Diversion I expressed the opinion to a senior staff officer of Air Support Command that we would be well advised to fit a similar kit to our squadron aircraft.
The cost was peanuts, about ₤6,000 per aircraft plus time to fit it.
I was grandly told, as he had bigger rings than I had so he knew much more about flying Pumas than I did, that it was totally unnecessary as in a war they would be switched off.
My contentions that I had joined the Air Force to ensure that there was not another war and that we were wasting time and money getting lost without proper equipment were totally ignored and eventually my argument was terminated by a fellow officer who led me away before I got court martialled.
I don’t know what they have now, but I hope it is better than a map, stopwatch and a wavy Decca map.
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I don't know either since I left before they had their "end of life, sorry, mid life update". However, the original VOR receiver / controller boxes in the HC1 were physically labelled VOR/ILS. I was told all they lacked was the correct aerial fit.
Decca letdowns were OK though - as long as the crewman did the mental gymnastics properly.
Decca letdowns were OK though - as long as the crewman did the mental gymnastics properly.
I am sure one of our ATC friends will correct me, but I thought that ATCOs had still to practice giving SRA as a part of their local (re)validation. I know of one or two civil airfields where ATCOs are generally happy to give, or may even volunteer, an SRA, when an aircraft is out doing IFT.
Shy: you're right about the Puma HC1. The FAF version had the (then!) full kit, but having only a TACAN and one VOR (in addition to ADF) meant that we could not fly in the Paris Class A airspace.
Another aside: The B412, when introduced to DHFS, had the most advanced fit (excepting SK Mk 3a, perhaps) of any in-service UK mil helo then; coupled autopilot which would fly you down the ILS and level off at 50 ft over the runway. The op SAR version, with the four-axis SPZ-7600 AP, will do the above AND slow you down to 70 KIAS descending through 200 ft. This is also a common AP in S76 and some other types, and most offshore helos of the present generation have this plus other features.
Shy: you're right about the Puma HC1. The FAF version had the (then!) full kit, but having only a TACAN and one VOR (in addition to ADF) meant that we could not fly in the Paris Class A airspace.
Another aside: The B412, when introduced to DHFS, had the most advanced fit (excepting SK Mk 3a, perhaps) of any in-service UK mil helo then; coupled autopilot which would fly you down the ILS and level off at 50 ft over the runway. The op SAR version, with the four-axis SPZ-7600 AP, will do the above AND slow you down to 70 KIAS descending through 200 ft. This is also a common AP in S76 and some other types, and most offshore helos of the present generation have this plus other features.
Last edited by idle stop; 23rd Jan 2008 at 16:57. Reason: typos
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Yes, the S-76 SAR model I used to fly in a previous job had the same facilities as those 412s plus "Approach 1 / Approach 2" and "Mark on Target" modes.
Approach 1 would take you from cruise altitude & speed to 60 kts & 200 feet radalt, with the aircraft steered in heading mode (aircraft follows the set heading bug).
Approach 2 went from 200 ft / 60 kts to a 50ft radalt hover.
Mark on target was used when overflying a survivor; the aircraft would automatically fly a teardrop to bring you into an into wind hover at 50 ft radalt, about 100 metres short of and slightly left of the survivor, i.e, bring you to a position to run in to begin winching.
A bit better than an SRE approach.
Approach 1 would take you from cruise altitude & speed to 60 kts & 200 feet radalt, with the aircraft steered in heading mode (aircraft follows the set heading bug).
Approach 2 went from 200 ft / 60 kts to a 50ft radalt hover.
Mark on target was used when overflying a survivor; the aircraft would automatically fly a teardrop to bring you into an into wind hover at 50 ft radalt, about 100 metres short of and slightly left of the survivor, i.e, bring you to a position to run in to begin winching.
A bit better than an SRE approach.