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Memory is a bit vague but I think it was XV101 after being in the hangar undergoing mods for an extended period. On the flight test, the stick shaker went when the flaps were moved from approach to land. Gave the crew a bit of a start it did.
The system was re-calibrated and sent up for another flight. Same result. The problem was finally traced to corrosion on the contacts of the micro-switches in the flap drum switch. Where they hadn't been used for some time, they had oxidised and affected the resistance of the circuit, so in effect, it was incorrectly calibrated. Best bit about the stick push had to be the klaxon though. |
Stall Protection - course notes
Hello Davita, BEagle and Saintsman,
Thanks for your anecdotes. Thought I'd better look at my pilot's conversion-course notes (Gatwick Bee-Hive, 1971). They are a mixture of my handwritten notes and diagrams of our Pete Horscroft's lectures on the subject, a few diagrams from the maintenance manual, and extracts from the ARB Flight Manual (Doc.No.VS.5.2). The latter document may be specific to the Type 1103/1109, but it seems unlikely that the stall protection would have varied from other types. I was immediately struck by how sophisticated the system is, and reminded of the 13-point checklist that the copilot had to perform on it during the pre-flight checks at the beginning of a crew's stint. We and the F/Es certainly had it tough in those advanced, but BITE-less aeroplanes... Had forgotten that the duplicated system means there are actually 2 AoA probes per side (one very close above the other, No 1 system probes being on the left). What I remembered well was that each heated probe is small, and its vane is hidden inside a slim conical cover which admits the air through slits in its leading edge. This is unlike the BAC 1-11 (despite the systems being otherwise similar), or any other a/c I flew subsequently - all of which have larger, uncovered vanes. You may recall better than I that: the L/H-side probes are nominated #1 system, and the R/H-side #2; the lower probes signal the "AUTO-IGNITION", e.g., #1 (left) actuating the #1 igniter system in each engine; each upper probe signals only its "WARNING" (stick-shaker & knocker) system - #1 (left) actuating the L/H control-column and arming the #1 "IDENT" system, and #2 (right) actuating the R/H control-column and arming the #2 "IDENT"; each lower probe's second task is to signal the "IDENT" part of its system - each system having its own horn, but either system able to actuate the pusher, fitted only on the L/H control-column. The AUTO-IGNITION mode has no phase-advance, apparently, unlike the warning and ident modes. That contradicts a comment in my previous post (re the clean-up phase hot/high/heavy) *. According to my handwritten diagram and notes, it looks for an AoA which is modified only by Slats angle and Mach. The WARNING mode looks for an AoA which is modified by: rate of AoA **, Slats angle, and Flaps angle, but not Mach (?). This is further modified by an LRM (lift-rate modifier) for normal accelerations > 1G. The IDENT mode obviously looks for a higher AoA than the warning mode, but uses the same parameters of modification, including the LRM one. Davita, I cannot find a figure for the pilot force necessary to overcome the push, but I thought it was a high 2-digit number in pounds? BEagle, You seem to have been keen on slatless approaches, so guess you were a base-trainer? Recommended approach speed slatless with full flap is VAT +20 on our 1103s/9, so I presume the VAT +10 was trainee error? ;) Yes, out of Nairobi or even Entebbe for London, we used to fly absolutely level (if not a tad downhill, although that was frowned upon) for the clean-up, and some F/Es would gratuitously offer us full throttle in anticipation of the auto-ignition lights coming on. As you say, there was quite a lot of pushing to be done on the TPI levers (but nothing like as much as a G/A on a jet with underslung engines). Flap-limiting speed was 229, and V2 +60 about 224. Added by edit (2014-02-23) * So, when the F/E reported the auto-ignition coming on, it was caused by the actual AoA reaching the auto-ignition threshold - not a phase-advanced engagement (combination of high AoA-rate and AoA, as in turbulence). ** (sometimes referred to as "phase advance") |
I used to get a couple of spacies on their summer camp to hold the columns while I tested it, told them to hold tight and it really did demo to them the force it pushed with, even though I'd told them what would happen, I then used to quiz them to see if they knew why it did it.
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I have not a clue whether it is correct, but I seem to remember a figure of 80 lbs as being the push force on the stick pusher.
It was one hell of a long time ago!! Alan |
...so I presume the VAT +10 was trainee error?
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BEagle,
Sorry Sir! (And me a mere stoker.) But you said it was slatless in your post. 40 years is a stretch of the memory... I now realise, however, that you had already modified the VAT to suit the landing config, whereas the VAT I was referring to was the VAT for full slats and full flaps. So on that basis, you got the shaker at VAT +30. That's interesting. (IIRC, the increments for slatless and flapless are the same, at 20 kt?) |
Alan,
"It was one hell of a long time ago!!" Yes, 40 years and 5 jet types in my case. And you and I were daggers-drawn in those days: you at the PanAfric and we at the Norfolk! FWIW, 80 lbs was about the figure I too had in mind. |
Not my sale and I know there are a few VC Ten crews and even current members on here. There is a bit of VC Ten history on EBay.
Didn't know if I should post it.. Brian Trubshaw EPNS Silver Presentation Tankard VC10 First Flight 1965 | eBay |
Possibly acquired by the vendor at the recent Dominic Winter sale where Trubshaw's logbooks and a lot more were on offer.
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Sorry Sir! (And me a mere stoker.) But you said it was slatless in your post. What I actually posted was: The only occasions I recall getting the stick shaker during normal flight was if the AoA probes hadn't been correctly set up. However, the lift rate modifier and pahse advance were more sensitive during slatless approaches and would often cause a brief rattle during the approach at around VAT+10. We had one K2 which had never had the wires from the lift rate modifier connected - some idle git at the factory had just stuffed the wires behind the unit and it wasn't discovered until 'Scrapheap Challenge' at St Athan did a major service.... I had the stick pusher on a flapless approach once - and yes, it can be overpowered by the pilot! The aircraft had been sitting around at Incirlik for weeks and was just back at Brize - this was probably the first flapless approach it had flown for months. We later figured that the AoA probes were sticking due to all the dust and lack of washing at Incirlik, so had perhaps jumped and detected a spurious high rate of AoA change.... After which the aircraft were given a good clean when they returned from Incirlik. |
Well then, Sir,
May I respectfully ask that you read precisely what I wrote? HINT: I was responding to your first paragraph... |
"Maintain point eight four, thank you Mr Scott!"
:p The point was that all VAT references in my posts do of course concern configuration-specific VAT.... Did you ever practise total hyd fail approaches? I.e. no flaps, no slats, fixed TPI, free-fall U/C.... Around normal VAT+40 at touchdown, with probably only reverse thrust to slow the beast on landing. I only tried it in the simulator; it wasn't even a training requirement for our crews to try it, but it was quite an interesting challenge....:\ |
Quotes from BEagle:
"Maintain point eight four, thank you Mr Scott!" WILCO, Zirr ! "Did you ever practise total hyd fail approaches? I.e. no flaps, no slats, fixed TPI, free-fall U/C.... Around normal VAT+40 at touchdown, with probably only reverse thrust to slow the beast on landing." No... Should that be normal VAT +45? 3 full (non-antiskid) brake applications from the brake accumulator, or was it only 2? I was going to say that the 'Ten was unusual in not relying on system-hydraulics for the flying controls, but then I remembered that my next type, the B707 (if you can't take a joke, etc... :sad: ) had ailerons and elevators that needed neither electric nor hydraulic power, and worked pretty well. "The point was that all VAT references in my posts do of course concern configuration-specific VAT...." Yes, I'd almost forgotten that the VAT is config-specific. On Boeings and MD, IIRC, the equivalent to VAT is VREF, but the latter only has one value: that for full flap with full L/E devices. Every combination of L/E devices and flaps has its own increment above VREF. VREF is always bugged on your ASI. You then add any config-required increment for the landing, and bug that as well. During the intermediate approach, as you you extend whatever devices are available, you fly the appropriate increments above VREF - like you do on a normal approach. Don't know about Lockheed. Did you fly the Tristar? STALL PROTECTION Can anyone comment on the lack of a Mach correction (if my course notes are correct) on the activation AoAs for the shaker and pusher, and the lack of LRM on the auto-ignition? |
Originally Posted by Chris Scott
(Post 8168164)
On Boeings and MD, IIRC, the equivalent to VAT is VREF, but the latter only has one value: that for full flap with full L/E devices. Every combination of L/E devices and flaps has its own increment above VREF. VREF is always bugged on your ASI. You then add any config-required increment for the landing, and bug that as well. During the intermediate approach, as you you extend whatever devices are available, you fly the appropriate increments above VREF - like you do on a normal approach.
VREF30 would be bugged with a fixed bug on the ASI, the moveable "command bug" set to the approach speed, and another fixed bug set to VREF30+15kt which would be the speed to be flown during the initial stages of the go-around (prior to acceleration and flap retraction) |
Strewth moggiee,
That sounds like a poor-man's A320 (sorry) ! Does the flap also go up one-step immediately on go-around, giving the applicable VREF +15 regardless for the initial climb? Must admit my last Boeing type was the B707-320B/C ("advanced") :8 , and I couldn't find the flight-patterns booklet before finalising my post. |
RIP VC10
So long, and thanks for all the gas. |
Originally Posted by Fox3
So long, and thanks for all the gas.
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[Quote]So long, and thanks for all the gas[Quote]
Was it the late 80s that we were running empty jets backwards and forwards across the pond on so called trainers to burn gas otherwise our allocatiom for the following year would be reduced? Sorry working on smart phone can't get 'quote' thing to work. Not going away from pool and cold beer to post on PC :p |
Yes, in 5 working days we used to teach 2 crews oceanic NAT procedures and US civil/mil operations in bother benign and austere environments. A total of 10 legs, 5 for each student crew. This enabled us to clear the student crews for out-of-area operations with reasonable assurance that they would be able to cope on their own. It also gave the GEs a chance to train up new GEs; on each day they would adopt one trade under the supervision of the 'real' GEs - they were able to pack an enormous amount of trade training into those 5 days. Our 'States Trainers' were always programmed to suit the training requirements of both aircrew and ground crew.
We then taught the student crews AAR trail procedures on a weekend trip to Cyprus / Palermo with 4 x FJs. 2 x 2 outbound, with one tanker landing at Palermo and the other in Cyprus. Then a 4 ball inbound, with a tanker/tanker RV east of Palermo; one tanker taking the 4 ball the rest of the way, the other night-stopping in Palermo. A proven, effective way of training which used to turn out crews trained for world-wide AAR operations. It worked well for many, many years.....until, that is, an interfering micro-manager decided to change everything, without any good reason except that he had to know best. Probably the worst Sqn Cdr we ever had....:* And both the States Trainers and Trails involved quite an element of fun, of course! |
I've posted this in the Aviation History & Nostalgia corner but as it involves VC10s...: http://www.pprune.org/aviation-histo...ml#post8170681
I would appreciate it if anyone could add some more details to this story! |
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