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Airprox question?

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Airprox question?

Old 16th Mar 2007, 22:03
  #1 (permalink)  
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Airprox question?

I am interested in views about the following incident.

Fighting a 30 knot head wind in a c150, open FIR, airspeed 85-90 knots ground speed around 60 knots, east - west north of Cranfield and working Cranfield approach, I am aware of traffic doing IFR approach work into Cranfield. The track takes me just south of Bedford and Poddington disused. I am at 2300 feet and there is jetstream following an IFR approach procedure. Viz approx 25 to 30k. I see the jetstream out of my left (port window) level reported at 2500 feet and the aircraft is heading directly towards me with landing light on. I have reported my level and position on a regular basis at the request of Cranfield approach, the Jetstream and I both know the situation.

I expect the Jetstream to turn slightly to the right and pass behind me and observe for a couple of seconds - no action. Given the speed of a jet I have few options, turn right, no dice - he is much faster than me, turn left - head on collision, go up - he is supposed to be higher than me - not an option so I opt to descend and lose sight of the Jetstream.

I hear on the radio - "that Cessna was 50 feet below, that Cessna was 50 feet below"

I intend to file a CHIRP report.

What would you do?


Last edited by Bob the Hamster; 16th Mar 2007 at 22:16.
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Old 16th Mar 2007, 22:20
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Have a word with Cranfield and the operator of the Jetstream.
By all means file a Chirp report, but one thing I have to ask is whether you thought of moving out of the way yourself - there is no point standing on the Rules of the Air if the other guy isn't going to follow them.

They may be flying IFR and are not looking out of the window, so the 'see and avoid' doesn't apply to them.

If you always assume that the other guy hasn't seen you (or is an idiot) and take early avoiding action, even though you may have right-of- way, you are likely to enjoy a long flying career.
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Old 16th Mar 2007, 22:28
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I admit that a couple of seconds is a long time when something is approaching at speed, and that I should have reacted immediately. I am not absolving myself and I think it is better to make a confidential report, without apportioning blame, than to ignore the incident altogether.
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Old 16th Mar 2007, 22:28
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I am at 2300 feet and there is Jetstream following an IFR approach procedure.
You might have right of way but as you have realised he is on a procedure would it really have been unreasonable of you to have tracked clear of the approach path? Certainly what I would have done if I knew someone was following a procedural approach.
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Old 16th Mar 2007, 22:29
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Can you give us a little more info? Is Cranfield radar controlled and were you in controlled airspace? What sort? E? D/C/B? (I don't have a map here.)
What sort of service did you formally get from Cranfield? RIS, RAS, FIS? Did you get a squawk? Mode A or C? And I assume you were a VFR (SVFR?) flight?
Was your QNH/QFE setting correct, were you at the correct altitude/height for your clearance?
Were there any other relevant communications related to this airprox, before or after it happened? Specifically, if you say that you were both aware of each other, was this because ATC gave you traffic information or was it circumstantial, pieced together from the others' radio transmissions?
Did you get the callsign of the jet (don't have to reveal it here)? Might be really useful for the report. Did you write down the exact time - same reason.
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Old 16th Mar 2007, 22:37
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Foxmouth, I agree in principle but there is little time and nowhere to go. In hindsight it would have been better to descend much earlier.
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Old 16th Mar 2007, 22:45
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Class G airspace on the QNH issued by Cranfield and there is no Radar service just an FIS. I was asked to transmit for DF when clear of the approach path. No idea of the other aircraft's reg or particualrly interested as it is to me a general saftey issue rather any real gripe from my perspecitve. Flight was VFR by the way and altitude was correct - before the descent.

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Old 17th Mar 2007, 08:51
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Yes you are quite right that "see and avoid does apply". I phrased it badly, in that, certainly in my limited experience, some IR qualified pilots flying high-end, well equipped aircraft will be looking to practice their instrument procedures. There is a temptation to think that because they are following the laid down procedure, everyone else will get out of the way, or should not be there. At my local airfield, we have radar controllers, so Bob's situation should be minimised, although it still happens.

There is also the case that a VFR pilot can truck on blindly across a marked ILS approach line, so it does work both ways.

My response was that it is better not to argue with a bigger aircraft, but get out of its way as soon as a likely conflict becomes apparent.
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Old 17th Mar 2007, 10:18
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Firstly, if you feel your a/c was endangered by the proximity of another, an Airprox Report should be filed. The Jetstream crew may have have already done so. You're obviously intent on learning from the experience (fantastic! ) so give others a chance too!

Secondly, even if you've spotted the traffic don't assume he's spotted you. You may be snugly hidden behind his window frame. Thus also don't assume he's going to manoeuvre lear of you.

Thirdly, be careful about fixating on reported height unless you are certain of which pressure setting you're both on.

In general, it's prudent to keep an extra-special lookout around IFR let-down areas. The a/c flying the procedures will of course be that much more "heads down" following their instruments.

Anyway, good on ya for talking about it!

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Old 17th Mar 2007, 10:45
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What I mean by altitude was correct is that the QNH was set correctly and the altitude was 2300 feet as stated, neither an intimation that I was necessarily in the right nor a fixation with altitude. The Jetstream was outbound so had not yet turned onto the approach path printed on the chart.

It seems that the moral of this tale is that the IFR let down area is a dangerous place to be, and not obvious to those who may not be trained in IFR approach procedures and unaware of the extent of the approach patterns involved. I always contact ATC at the airfield concerned, there were a number of aircraft reported to ATC that day that were not in contact with them.
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Old 17th Mar 2007, 12:45
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Cranfield is a very busy place! I am obliged to fly close by there quite often, batting along quite quickly. Sometimes, such as yesterday, I find it extremely difficult to get a word in to announce my presence, especially when a single controller seems to covering more than one frequency and doing everything for everyone. It's made worse because the agency I really need to talk to is Luton Radar because I usually need an airspace transit from them when going southbound. Thankfully, I fly with the luxury of a traffic avoidance system these days, which is a godsend as far as increasing situational awareness goes. Obviously, you don't have that luxury.

Rather than submit a report (an AIPROX would perhaps be more appropriate than a CHIRP), I would just learn a personal lesson from your experience and perhaps think about what you might do differently next time. For example, as you say, you could have descended earlier, or planned to fly further north. I would personally aim for at least 500 feet altitude separation if possible.

I note that you spotted the other aircraft first because he had a landing light on - there's something else to think about, .... your aircraft, in common with all light aircraft, presents a very small visual cue. A bright light can help increase your contrast. I often put on the landing/taxy lights in a busy traffic environment, especially if TCAS says something is ahead at a similar level but I haven't yet spotted it. I do often spot aircraft first (not saying I get 'em all) and notice that other aircraft do often use their lights to acknowledge they have also seen me.

Bear in mind that the airspace between EGTC and the CIT tends to be where the other (two) pilots' eyes will be inside more than is ideal. Even if it's an examiner and a candidate, the examiner will be watching how accurately his pilot is finding the beacon and flying the procedure. I avoid that airspace if possible, although in Class G anyone is at liberty to transit through it.
Yesterday I couldn't avoid it on the way from Luton and was therefore extra vigilant. I made sure I spoke to ATC as early as possible, made myself as conspicuous as possible, looked out as much as possible and included the TCAS in my scan.

Hopefully the other pilot will also be more vigilant in future and aim to increase his own situational awareness as a result of his part in your "encounter". He was in Class G after all and was also responsible for lookout, despite being on the procedure, even if declaring IFR (I take it you were both VMC, I know the Wx was quite good). He might have had IF screens up, which certainly wouldn't have helped him.

If he has submitted an AIRPROX report, you will get your say in the process and it isn't there to apportion blame. You saw him in Class G and took avoiding action. He saw you later and closer, possibly when he felt it was too late for him to resolve the situation and it startled him. Had you not turned, he might never have seen you, although you would have been closer to him. If it is reported, I would put money on it being classed as a category B or possibly a C, btw.

AIRPROXes are an emotive subject for most pilots. The last time I submitted an AIRPROX, some while back, it was because we saw another aircraft very late and had to take fairly energetic avoiding action to avoid a collision. The other pilot didn't appear to have seen me as he didn't take any avoiding action (as he should have done iaw rules of the air). When asked by ATC he initially denied it could have been him at all (no doubt about that, I read off his registration as it went left to right, less than fifty metres ahead and only slightly above us, as he descended. Later he got very grumpy and declared in his report that he considered that it was up to other aircraft to be on his homebase "A/G" frequency nearly seven miles from that location, rather than the radar unit I was in contact with, and was to land at. ATC didn't see him on primary radar (although they saw us) and he wasn't using his transponder.

Take care.

Last edited by ShyTorque; 17th Mar 2007 at 15:57. Reason: grammatical error!
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Old 17th Mar 2007, 13:04
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Sorry Bob, what I meant is that unless you know he's on the same pressure as you (and that he's set his altimeter correctly!), his being at 2.5 doesn't necessarily mean he's 200' above your level.

I should perhaps have said "rely" rather than "fixate"!

I would guess that any investigation would at best conclude "late sighting" by one or both pilots.

BTW, further to what Shy said, when I was flying in the States there was an "Operation Lights On" campaign, basically aimed at small aircraft in a busy environment. The gist was an encouragement to fly (during daylight) with landing lights and strobes (if fitted) on, making yourself that much more visible.

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Old 17th Mar 2007, 20:37
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I once had a near airprox,it probably was but I was more annoyed than anything else afterwards!
In the cruise at prob 2500 ish on an FIS I was notified of similar level traffic out to my left,the vis was not fantastic at the time so when I finally spotted him we were too close for comfort.
I had right of way but rather than prove a point I took fairly sharp avoiding action,enough to make my pax(a ppl) jump!
I think the sight of the underside of my a/c woke the other guy up who promptly shouted "AIRPROX!" down the radio
He then said "I think we will leave it at that"
I felt we both learnt something-me fly at a less common height choice, him-well he probably remembered the rules of the air regarding converging a/c.
No airprox was filed,he pointed this out in the air,and to be honest I didn't want the hassle.
I think a CHIRP report would have been worthwile though.
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Old 17th Mar 2007, 22:39
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Surely it's basic airmanship not to fly across an instrument approach, especially if you know there's traffic on it. If you have to, then be somewhere the other guy isn't going to be, i.e higher or lower. If memory serves the base of controlled airspace around the CIT is FL55.

Secondly, if you are going east to west and he's coming down an instrument approach on r/w 21 then HE has right of way..... and doubly so since he's landing.

Don't bother with an airprox. Learn from it, have chat with Cranfield and even the jetstream crew (I can put you intouch with them if you like).
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Old 17th Mar 2007, 22:40
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Cranfield is a very busy place, not just from visiting larger aircraft but from the VAST amount of Instrument and Commercial training that goes on. It is in Class G with no RADAR but the instrument flute is clear marked on the VFR chart. Yes you have every right to be there in the Open FIR in Class G but good airmanship should dictate that you give the IAP a wide berth.
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Old 18th Mar 2007, 08:26
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A few people have mentioned not flying across an instrument approach, and while that's obviously a good idea, if you've only got a basic PPL nobody tells you anything about instrument flying.

When I was learning ATC would sometimes say 'I have have traffic on an instrument approach' which meant absolutely nothing to me - if they'd said on right base I would have known where the plane was. I discussed this with my instructor and he ran through instrument procedures with me so I could have a basic appreciation of what was going on.

However, you could do your 45 hours, get your license, and not even know what an ILS was, so unless ATC keep you out of the way you wouldn't have a clue that you were interfering with instrument traffic.
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Old 18th Mar 2007, 08:50
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But as Bose has said about the instrument flute on the chart, you should know what this means as part of your PPL training, no excuses on that part, after I did my PPL I used to fly past Filton & Staverton and was aware of the flute so I tried to fly as wide as possible and as high as possible,
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Old 18th Mar 2007, 10:38
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...you should know what this means as part of your PPL training
Well, after my PPL training I sort of gathered that the funny symbol meant people might be flying in on it, but how high? How far out? It was only when I got my IMC that I realised that people might be flying OUTBOUND on a nearby track too.

Maybe this needs rectifying in the PPL syllabus, and it's worth mentioning from time to time in GASIL, Safety Sense etc. But the fact remains, there will be planes out there not squawking, not talking to the tower and not really looking. Anyone flying an approach in Class G in VMC must treat it as bandit country, just like any other Class G. "It was the other guy's fault" is a great epitaph.
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Old 18th Mar 2007, 12:39
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I also give the ILS flute a wide berth which,to me at least, seems to be a simple safety decision. But I have to admit that I have generally thought of it as an approach path although aircraft will certainly depart via the indicated path. obviously the flute starts at ground level, but what is the height (AAL) of the outer extremity? That info seems to be the most useful bit for the purposes of planning a flight which takes me close to an ILS equipped airfield. Perhaps somebody could point us to a diagamatic profile of the ILS path on the web.
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Old 18th Mar 2007, 13:13
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Perhaps somebody could point us to a diagamatic profile of the ILS path on the web.
Err... www.ais.org.uk, in the AIP, AD, Aerodromes - Specific...?

Even if you don't understand the text information on the charts, the map is clear enough.

I agree - some awareness of what is going on with OCAS IAPs would be a good idea for all PPLs. And NPPLs. But perhaps we are in danger of 'gold-plating' the licenses again and increasing the training costs?

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