Chinook - Still Hitting Back 3 (Merged)

[jayteeto]

If you fly in route mode, the RNS 252 changes waypoint automatically. The PRC theory was bo**ocks and still is bo**ocks.

[walter kennedy]

And just what mode do you think the SuperTANS was found to have been in? - get it right.

[Boslandew]

Jayteeto
Your reply shows that I am not trying to split hairs.
I do not know at what airspeed an HC2 at reduced weight is practicably flown. Up to 140 knots, and I accept your plus one or two knots, a set of VFR limits applies. Recent posts have given three slightly different versions. At 150 knots, as you say, another set would apply, that is 5.5 kms and a "greater" cloudbase which, despite more than one request from me, no-one has yet been able to quantify.
We are told that SH "routinely" fly in minimal weather conditions and one of the three sets I mentioned was suggested to be 100'/500 metres. I assume, and I'm sure someone will correct me if I'm wrong, that "routinely" means in accordance with RAF SH Rules. This can only mean "below 140 knots" airspeed.
If all that is so and if no-one can know what was seen from the flight-deck, and this is my whole point, what factual grounds are there for the claim and thus the verdict, that negligence had occurred by the time the way-point was reached and, by extension, that any subsequent possibilities, FADEC problems, control jams, were irrelevant? Put another way, it is entirely possible that the aircraft could have passed the waypoint, still been within its SH VFR limits and then suffered a malfunction. Doubt must exist. Forgive me if this is rehashing old ground but it seems essential to me to spell it out.

[Arkroyal]

Oh, and Caz...

Another reason for my absence over the past months is that John Blakely, as so eloquently demonstrated in his last post, can say all I need to say, and more much more calmly, succictly and authoritatively than could I.

Thanks JB, you sum up the injustice so well. I'd bet that The AMs are by now wishing they'd let their better judgement rule their vindictiveness.

Now their hard line, based on insufficient evidence will surely be haunting them, and hopefully keeping them awake at night.

I sincerely hope it comes back to bite their backsides. And soon.

[antenna]

I would recommend, Boslandew, that you read the conclusion of the House of Lords report, especially, though not exclusively, from paragraph 135 onwards, in which the committee studies the various hypotheses. It is a useful synopsis. The Lords study the WP change, VFR/IMC, the Boeing simulation, the MoD's incorrect use of TANS for historical purposes.
Their sign off paragraph states:
How could it be that a very experienced crew, having planned to fly VFR, having taken when probably visual with the Mull the appropriate steps to alter course, when there was nothing to prevent them flying northwards within sight of the coast, flew into the Mull? It is as Sir John and Sir William speculatively described "incomprehensible" (Q 342) and "astonishing" (Q 377). We shall never know.

To the point.
Hell, on top of the potential tie-bolt problem I referenced some days ago, they even point to the contamination of hydraulics on ZD576, which the AAIB specifically did not rule out as a(nother) possible cause.

[jayteeto]

Walter, if I got the 252 mode setting wrong, I apologise. I actually have no idea if they were in route or direct mode. However my main point about the aliens using martian guidance rays to entice the aircraft still stand. Total Tosh. Ooops, sorry, yours was the PRC theory so that is a different answer.......... actually no it isn't. Martians/PRC.....same probability.

[ExGrunt]

Boslandew,

I worked in the Buzzard Cell at BBK in the late '80s and the limit in use then was 100' cloudbase and 1000 metres vis.

In practical terms there was a lone tree on the ridge to the east of BBK. If the tree was visible then all normal operations - trash, pax etc went ahead.

Taskings were not broken down by type as the most efficient usage of hours saw a cab tasked to do several different tasks in one go.

Separately:

If you take Mr Holbrooke's statement that he could see the wall of the lighthouse at the base of the cloud and contour that round to where it intercepts the Boeing simulation you find that the position of the waypoint change is 973m from the cloud covering the hill.

EG

[Boslandew]

ExGrunt
Many thanks for the info, it all helps to give a better picture of the flight. I left the mob in 1975 for the North Sea so I'm a bit out of date. I wondered if there might be different limits akin to civilian VFR limits for such a flight as this, an A to B flight with civvies on board, but there clearly aren't.
At the waypoint, it would appear that there were grounds for believing that VFR visibility conditions (1000metres) existed.
Just to put me out of my misery, could someone tell me what cloudbase limits for a military helicopter above 140 knots are when vis limits are 5.5 kms?

[Seldomfitforpurpose]

Bosland,
Try not to get too wrapped up in the distinctions you are trying to make as in this case I do not believe they were applicable.

The "Civilians" you keep referring to were anything but, they were members of the security services and were flying in direct support of the Operation that was NI at that time. As such they would have had the same "standing" as regular troops, this practice continues today and you would be amazed at the amount of "civilians" being flown on a day to day basis in current areas of op's so I believe you are heading up a dead end with that one.

As regards the 140 Kt notion it has already been explained quite eloquently that vibration in the Chinook above 140 Kts was something to behold and, whilst I have no first hand knowledge of authorising I doubt the weather minima for flights above this speed would have been a factor that was considered.

[Boslandew]

Seldomfit forpurpose
Many thanks for your reply
I'm not trying to make distinctions so much as to see if they exist, the better to understand the flight. Forgive me but I persist because it is not easy to get my questions answered. Perhaps I'm not phrasing them well
I asked what military VFR limits were and got three different answers.
I asked some posts ago if int personnel counted as military and received no response until yours, so assumed that they were not or that it was classified info.
It took two or three requests to get an answer to my question as to whether there would be a difference in met criteria/any criteria between a tactical flight, say a troop insertion, and a transit flight carrying civvies (see above).
I am aware of Chinook vibration - I flew them for three years/2000 hrs, invariably at MAUW. However at reduced weights, (say after 10000 lbs of fuel had been burnt), cruise at VNO, 140 knots, was quite practical. I understand the military max is higher than 140 knots hence my query. The aircraft in question was at reduced weight even if not by 10000 lbs
Finally, after four requests, and forgetting for a moment the flight in question, could someone please take pity on an old pilot and tell me what the cloudbase limits are for a military helicopter flying above 140 knots?

[ExGrunt]

Boslandew

I agree with SFFP, pax were pax and were never classified by type. Sorry I did not make that clearer.

EG

[walter kennedy]

To anyone trying to fathom out what may have happened here I cannot emphasise enough the importance of the reference to a large scale chart or map with the critical points marked as accurately as possible and with the right magnetic variation of the time applied to any bearings (a contemporary air chart would be a bonus) – it is worth the effort as many things would be so much clearer – an example is the situation that they were in at the position where the waypoint (in the SuperTANS) was changed (for brevity WPCHX hereon).
.
There seems to be a perception that, at WPCHX, if waypoint B (corresponding to Corran) had been actually used and the steer information to it had been enacted that the change of course to B, at that point, would have got them out of trouble.
This was not the case as the bearing to B at WPCHX was 020M – which would have had them heading for the very highest part of the Mull.
Further, to have continued to waypoint A before turning towards B would have obviously had the same result.
The literal route from Aldergrove to waypoint A then B was not on at such a low level whatever the conditions – A could only have been an aiming point (for the sea crossing) to get to near the light house in VFR conditions (the “official” line) or they had some purpose to go in there.
.
To have cleared the high ground (of the Mull) by turning before waypoint A to the (direct) bearing to B (Corran) would have required action over 6 nautical miles before WPCHX.
Simple pre-flight chart work, when presumably they selected their waypoints, would have told them this – they would have known that, as close in as WPCHX, if they had changed their mind about getting close to the landmass, a turn of at least 15 deg left would have been required.
Bearing in mind that they should have been able to see the Mull (mist on the slopes and topped with a low orographic cloud – very nasty to approach without good reason) from a long way off, it seems strange on a ferry flight to have left the decision point so late (WPCHX is damn close in) which would have required effectively some back tracking.
.
While in good conditions it would seem entirely reasonable to go to the Mull and then “handrail” up the coast for a variety of reasons, it seems strange given the local weather on the Mull that they simply did not turn to Corran earlier in which case they would have not had any worries about high ground for another 30 miles or so – and even at that point, a small deviation along the Sound of Jura would have allowed the whole trip to have been completed at really low level if required (also not forgetting that the general cloud base in the region was significantly higher than the local orographic loud on the Mull itself and so even this deviation may not have been necessary).
.
Given that they were in a hurry (or so it has been so often alleged), it is also surprising that, if this was a straightforward ferry flight, they did not route to Corran directly because the dog leg to the Mull was a significant excursion – if the weather had cleared, they would still have had a good view of the Mull.
Plotting on a large scale map or chart makes this obvious.
.
So there is a problem with the scenario of them just getting into trouble near the Mull while on a simple ferry flight as, according to the logic above, there would appear to have been a decision point much before WPCHX and there is no suggestion of malfunction or distraction back then.
.
Further, given that they were making a change of waypoint so close in, not only did they not steer away left but they steered right a whopping 8 degrees.
The track from WPCHX to initial impact was a beeline at 035M – which was the course setting on the handling pilot’s HSI.
This (as I have argued in previous posts) would suggest that the course change to 035M was deliberate and unhurried (in an emergency, would you fiddle with a course selector?).
What was on that heading? – no navaid AFAIK.
Some may say they had decided to go to high level and therefore more directly – but the bearing to Inverness was not 035M. Besides, there are many reasons put forward on other occasions that the alleged attempt to climb over was nonsense so I won’t go into that here – I will take it that they were not.
So why would the handling pilot (the driver) have a course setting of 035M on his main nav instrument? And what data could it have been acting on? (You would normally have something like a TANS waypoint or VOR driving your track bar on the HSI otherwise why bother with the course selector.)
The one thing that waypoint A and 035M have in common is that they both get you towards that landing area that I have referred to previously - but of course waypoint A had been de-selected.
Could there have been anything else thereabouts for them to have been using that day?

[tucumseh]

It has been established that Racal’s post-crash examination of the SuperTANS, data recovery and analysis was flawed. The methodology was not validated, meaning the conclusions are unverifiable. Unverifiable – like almost everything connected with the flight (although not the major airworthiness issues preceding it).

My opinion is that any talk of the SuperTANS in the above context merely lends credence to the MoD’s assertion that the complete Nav System was both serviceable and accurate, when the only “evidence” comes from this unverifiable source which could only examine one badly damaged component of a larger system. At the very least, that constitutes reasonable doubt.

Setting aside all the debate on airmanship and engineering (and we debate because we don’t know), the underlying issue is the MoD’s basic defiance of natural justice which, in their supreme arrogance, leads them to act as judge and jury in their own case.

[Chugalug2]

the underlying issue is the MoD’s basic defiance of natural justice which, in their supreme arrogance, leads them to act as judge and jury in their own case.

Agreed, tuc, absolutely! That gross monstrous machine has wasted billions upon billions of our money in supplying inadequate tat to our armed forces. The military leaders that inhabit its corridors have collected baubles and trinkets to pin to their chests and hang round their necks in doing so. The RAF ones in particular can secure sinecure posts with the very suppliers that produce the tat and gross the billions. But when that machine is turned loose on two decent gallant and sadly deceased junior officers, destroying their reputations unjustly and in the face of protest from the House of Lords, the then SoS, the Scottish FAI and their own peers, then justice cries out to be done. This will not go away, we will not go away. Again I say this is the RAF's Dreyfus case, a blot on its honour and proof that the MOD needs total reform, root and branch, to rid us all of this millstone around our necks.
Let Right Be Done!

[Sand4Gold]

could someone please take pity on an old pilot and tell me what the cloudbase limits are for a military helicopter flying above 140 knots?

Boslandew

I sense your frustration. There may be a reason why you’re not getting a reply to your question. I, and I am prepared to be shot down on this, cannot recall any ‘FOB/GASO/ASO’ - that governed SH rotary flying - referring to a greater visibility limit when flying >140 kts. This recollection goes back to my days with 38 Gp, 1 Gp and, of course, JHC. Whether this was by omission, or design, by the authors, I cannot say. Most routine planning by SH crews, as you know, was/is done at 120 kts as a ‘standard’; the need to fly at 140 kts on a regular basis was not a day-by-day requirement – or indeed possible with some aircraft.

First time contributor

I, like many, knew and flew with Jon, Rich, Graham and Kev – what I cannot come to terms with, still, is that the total tonnage of doubt that exists to date could stop a herd of migrating wildebeest in its tracks. Something is not right here; what is it we are not being told?

[Boslandew]

Ancient Aviator
Many thanks for your thoughtful reply. It seems clear, although no-one seems to be able to confirm it, that the military Chinook is not operated above 140 knots. I'm sure I have read that its VNE/VNO are higher. My enquiry is thus academic but like an itch I can't scratch. The MOD reply to the House of Lords Select Committee report quotes all met requirements below 140 knots and visibility requirements above 140 knots but only refers to "greater separation (than VFR) from cloud" One of the respondents to this thread says that different figures would apply at 150 knots, possibly in a Puma, but did not say what they are. I shall desist as my enquiry is now really outwith the true scope of this thread.

I was not aware of any 'standard' figures. In my day the humble Skeeter did everything at about 70 knots and the mighty Scout cruised at 100 knots.

[Sand4Gold]

Boslandew

I hope others will allow us a certain degree of leeway here; it would be wrong to suggest that military Chinooks do not exceed 140 kts IAS, I am sure they often do. You would have to get a Mk2 crewmember to give you the exact Vne - as outlined in the current aircrew manual/ODM. The Vne would be approx 20 kts higher, but do not quote me.

The Puma could rarely manage 150 kts IAS straight and level (s&l), most Vmax computations were between 130 -140 kts IAS for a given Mass/DA, but as the ‘ol girl’ gets heavier I’m sure she would struggle today to exceed >140kts IAS s&l – certainly would make your teeth rattle.

The 120 kts is a good planning speed, which, I’m sure you appreciate, gives you a degree of flexibility to increase your speed if you have a Time on Target to meet.

P.S. Your question was actually about cloudbase limits when operating >140 kts - same reply, not aware of these limits being stated etc.

[Boslandew]

Ancient Aviator
Yes it would be of great interest to hear what the manual performance figures are for the Mk2/Mk3 Chinooks and how they work out in practice. I don't know if there have been any aerodynamic improvements since I last flew the civvy version in 1984. The BV234 manual gave some very optimistic cruise figures. Virtually every takeoff from Aberdeen was at MTOW, 48,500lbs, when the book said the cruise figure might be 135 knots. In practice we accelerated by 'beeping' forward on the cocked hat until the co-pilot (in the max vibration seat) began to look blurred when reducing by a few knots until he came back into focus and stopped complaining produced the initial cruise speed, typically 115 knots.
As regards the Puma I remember one crew claimed to have crossed RAF Topcliffe at 175 knots in a low-level pass one day but on the North Sea I believe 130 knots was typical. Helicopters generally don't seem happy above about 135-140 knots although an S76 would do 145 knots. Judging by those figures, 120 knots would seem to be a very sensible planning speed.
I'm beginning to suspect, as you suggest, that the cloudbase figure above 140 knots is a myth so unquantifiable.
Regards
Boslandew

[walter kennedy]

It would be very interesting to have the opinion of any one who had flown any Chinook as to what the implications could be for the power setting as found in ZD576 - low/intermediate and matched, as I recall.
I interpreted it to mean:
matched implied that the power had been steady right up to the last seconds (no time for either FADEC or pilot to change it in the last manouvre, what with the intrinsic lags) - ie a planned power regime for a reason;
the level was insufficient to maintain a high cruising speed (as indeed, according to Boeing's analysis, it had slowed down air speed by 20kts);
therefore they had to have been slowing down steadily for some reason.
I have always reckoned that they had misjudged/been misled by about 1/2 a mile in their distance off the mist - with a power setting sufficient to just balance the weight, with no component of forward thrust (coasting and letting the speed wash off), how much more could it have been expected to have slowed down in 1/2 a mile?
If you reckon down to 80kts IAS, or thereabouts, then it could have been down to a speed at which it could pull up quick smart for a landing in a short distance, could it not? Which is another indicator that they were intending to either land or wave off at that area.

[cazatou]

Walter,

If they were down to 80 kts IAS in level flight, with no time to change the power settings, could you please explain the AAIB conclusion that the groundspeed at initial impact was of the order of 150 kts with the aircraft pitched approx 30 degrees nose up?