View Full Version : Flying a SID without VOR guidance (BPK)

21st Jan 2002, 04:25
Today whilst doing departures I had a KLM FK50 request radar vectors due to an inability to fly the BPK SID. BPK VOR was notamed out of service, and the crew said something about not being allowed to use the FMS. It was a busy frequency at the time with landing traffic as well, so I didn't have time to quiz the KLM further.

Can anyone shed some light on this, any reason why a crew would not be allowed to use the FMS?

Any thoughts appreciated.


21st Jan 2002, 04:43
I believe, if only one FMS is installed, due to the possibility of a map-shift, SIDs and STARs must always be backed up by raw-data. Thus probably the Fokker has only one Flight Management System, which rendered it unable to 'legally' fly the SID without the raw-data.

As far as I know, the same also applies to RNAV arrivals and departures, i.e. can only be executed by aircraft with dual and independent FMS/FMGC.

21st Jan 2002, 04:55
But what would you have done in the days before FMS?

Surely if BPK is off the air you would find some other way to navigate to said point - isn't this partly what is meant by "raw data"?

What happened to the old concept of navigation?

21st Jan 2002, 05:15
If by "old concept of navigation" you mean our old friend the Navigator, the last plane to use one was probably not even in a museum anymore!!

In the absence of such a master of the CRP-5 Whiz-Wheel, FMS is his substitute, and if used properly, generaly does a great job........although it occasionaly does fly you straight into a mountain (American 757, Cali, Colombia).

However, raw-data flying, although no longer primary navigation, is still necessary to back up FMS, even if dual FMS computers are installed.

Agaricus bisporus
21st Jan 2002, 05:17
I'm surprised the BPK SID was specified as the VOR was u/s. Surely with a fundamental nav-aid inop the SID itself is inop too, and some other means has to be founs to route the traffic, such as vectors or a different SID that does not use that navaid.

My inbound tonight was an unexpected ASKEY arrival which bypasses BPK instead of the usual LOREL for this very reason.

Willit Run
21st Jan 2002, 08:34
If the VOR was NOTAM'd out of service, and there was no other way to identify the way points, then RV was appropiate, but they should have never been given that SID if the VOR was the only way to identify the points. They're FMS could have been deferred for whatever reason, and lawfully unable to use it for whatever reason, but, then their ATC tape should have represented that they were VOR only. I think this may have been a mutual problem.

21st Jan 2002, 14:10
Thanks for replies, all good stuff.

There is nothing in our procedures about not allocating a SID if an associated navaid is out of service.


21st Jan 2002, 14:19

I imagine there is nothing in your procedures because it should be blindingly obvious that you cannot fly a SID if the facility is unserviceable.

Remember SID's are drawn up with no acknowledgement of the ability of a FMS.

Our minimum equipment lists on the 757 don’t say that you need 2 wings, but we wouldn’t get airborne without them both.. . <img src="wink.gif" border="0">

21st Jan 2002, 14:28
Not actually totally correct,sky9.I would refer to RNAV SID's/ STAR's ( AMS,GVA,ZRH etc) which entirely rely on FMS to use them.However, a SID that utilised an inop VOR does seem a bit odd,but there are alternative ways of finding BPK and radar vectors could be one of them, although it's slightly admitting defeat!!B/rgds.

21st Jan 2002, 15:28
There are quite a few aircraft flying around, without Area Navigation/ FMS /FMGS.. .There are many reasons why there may be a problem with FMS/FMGS/IRS/GPS etc.. .The point is this, what ever navigation equipment you have, if you are in any doubt as to it's accuracy, ASK ATC. They have a multi-million pound radar system for your use. I am sure that they would wish you to ask for help at an early stage, it is simple Airmanship.. .As to the F50 crew, WELL DONE, it may have been flying the other way with 400 passengers in the back.

21st Jan 2002, 15:54
Blimey,it's only finding BPK, as navigational feats go it's not exactly the dark side of the moon.Given,the ATC technology I'm sure ATC are only too happy to oblige with vectors and I agree it's the sensible option.Surprisingly,there isn't an alternative 'when BPK is u/s' SID (as already mentioned there is an 'ASKEY' STAR ).I'm always amazed when even on a technical(and fairly mundane) topic the dramatic tension is raised-400 lives at stake,brilliant airmanship from the F50 crew etc.... cheers.

21st Jan 2002, 20:16

I don't want to split hairs however I did write "you cannot fly a SID if the facility is unserviceable". An RNAV SID is precisely that, a Departure that relies on RNAV rather than a ground based facility.

22nd Jan 2002, 01:21
As a practical aspect, BPK can be found by following the chiltern 067 radial, the overhead indication given by the BPK DME, which was still working. Just coz its not the named VOR at the end of the SID, so what. It can be naviaged to in a straightforward way.

22nd Jan 2002, 03:08
cough - as a technical aspect, CHT is an NDB, not a VOR, so it doesn't have radials associated with it. You can only fly QDMs and QDRs from an NDB which are infinitely less accurate than a radial (and can be affected by weather conditions.)

Gonzo - as some of the other contributors have said, you cannot legally fly a SID (in the UK, anyway) if the primary navaid is U/S. Whether the a/c is FMS/GPS etc equipped doesn't come into it - I think perhaps a small slip-up in LATCC?

22nd Jan 2002, 03:40
Tired. The CAA on the IRT expects you to track VOR and ADF radials to the same accuracy. Just because it is easier to select the radial and fly the beam bar on a VOR doesn't mean you can't do it on an ADF/NDB set-up (point about NDB accuracy noted). Flew this departure the other day (in LNAV) but monitoring the CHT NDB, which didn't move from 067. As it is acceptable to fly the 057 to CHT, why not the 067 the other side? I think we are too accuracy conscious these days, having GPS and the like navigating us to within a couple of metres, but the system doesn't need to be that accurate. If it did, we would all have to fly double FMC, DGPS aircraft, etc, but we don't.

22nd Jan 2002, 03:47
ps, just in case anyne wants to look at the chart, it is <a href="" target="_blank">here</a>

22nd Jan 2002, 04:11
Blimey, can open, worms everywhere!

The KLM F50 did the same again tonight, and confirmed that radar vectors were required after CHT.

Surely though there is no real argument here? If you are happy to fly a BPK SID with BPK off the air, then fine. If not then we can give you vectors, or you can refile for a different SID.


22nd Jan 2002, 06:13
There used to be a time in the UK that when there was a significant outage of a VOR a temporary NDB was located at the site, usually I recall on 669.5 khz.

One wonders why this has not been done on this occasion or is this because of an assumption that most a/c now have an area nav facility such as FMS etc?!

I don't think anyone could argue with a pilot asking for vectors under the heading of airmanship - as has been said above if in doubt ask.

However with the London TMA bristling with other facilities (many of them "static free") I find it surprising that anyone would have difficulty flying this SID with BPK off the air, given a little bit of pre-flight planning to anticipate the challenge. This is not to agree that a SID should be offered where a significant facility is u/s.

Or is there a concern here that if the SID is not quite flown precisely big brother is watching and one might get a violation but if you have asked for a vector it's on the tape?!

22nd Jan 2002, 15:45
cough, NDB's don't have radials, they have bearings.. . If any departure requires an aid it's not up to pilot discretion to substitute.. . Flying to an aid is increasing accuracy, ie splays for msa's. Flying away from an aid is decreasing accuracy.. . If the aids specified you need it.

22nd Jan 2002, 16:02
This 'NDB'thesis is all very well when using 27L/R. .but the BPK 'VOR' is most definately a req'd. facility when departing 09R.The same problem occurs at places like MRS & FRA where only RNAV waypoints are now published.Pre-FMS generation A/C have considerable difficulty negotiating these STARS & SIDS with any measure of accuracy.The only sensible alternative is to request 'vectors'.

23rd Jan 2002, 02:46
Thanks, soddit, you saved me having to post that. <img src="smile.gif" border="0"> Cough, FYI, if my memory serves me correctly, the (CAA-mandated) accuracy of a VOR is +/- 2 degrees, on an NDB it's +/- 5 degrees. I'm sure someone will point it out if I've got the numbers wrong.

As cough and others have pointed out, in practice there's no reason why we can't track outbound on the 067 bearing from CHT and arrive in the general vicinity of BPK - I'm sure that ATC won't mind if we're 3 degrees out over such a short distance (would they even notice?? :) ). However, unless the law has changed since I last looked at it, (and, again, I'm sure someone will correct me if I'm wrong) it is illegal in the UK to fly a SID without the nominated navaid being serviceable. In the unfortunate, and hopefully very unlikely, event of an incident, the first question the insurance assessor will ask (as he's busy writing out a Refusal of Claim) will be along the lines of "So, Captain, at what stage did you decide to ignore the law and fly an illegal procedure?"

Sorry, Gonzo, my licence isn't worth it.

23rd Jan 2002, 04:09
I am fairly certain that our LATCC colleagues are not daft ( that should get me a few direct routeings) and they would not promulgate a clearance without good reason,BPK u/s or not.For those with long memories it is possible to find points in space through radials/bearings and distances from other stations and I'm sure BPK can be defined thus.If the F50 crew need any more help with their navigational endeavours they could try following the railway line north from Potters Bar,notwithstanding their heroic efforts so far (sense of humour alert).Toodle pip.....

Only A Few More Seasons
23rd Jan 2002, 04:49
Best fly out of LGW, very seldom do you fly the SID - nice and easy radar steers,not sure why they even bother publishing SIDs.

[ 22 January 2002: Message edited by: Only A Few More Seasons ]</p>

Long Range Cruise
23rd Jan 2002, 15:05
Numbers you mention seem to correct to my knowledge.

23rd Jan 2002, 15:11

Could you point me towards the legislation you describe, please? On a night shift tonight so a bit of light reading would go down well <img src="cool.gif" border="0"> .


[ 23 January 2002: Message edited by: Gonzo ]</p>

23rd Jan 2002, 17:29
"Hello Croyden, Hello Croyden, this is aircraft #1"

"Aircraft #1, this is Croyden, switch on your transmitter on for 30 seconds and standby for position report"

24th Jan 2002, 00:46
Gonzo, unfortuantely not, it's been a few years. It was in the AIP somewhere......!. .(That should keep you busy for the evening <img src="smile.gif" border="0"> )

24th Jan 2002, 15:57
Tired, now you're just being cruel. It was one night shift, not a whole 6 day cycle of nights!

&lt;&lt;Gonzo, unfortuantely not, it's been a few years. It was in the AIP somewhere......!. .&gt;&gt;

Caught your reply too late, but will try to look it up next cycle!


24th Jan 2002, 18:26
Can anyone at work look up the rule about dispatch in Europe without rnav?

I think it is now very difficult to fly IFR without Rnav. (from memory the detail of just. .how much you are restricted depend on which country you are in).