A flurry of soft hail hissed against the windscreen, building up a porridge-like sludge beneath the wiper blades. Through a brief break in the cloud I saw a heaving slate-coloured sea, flecked with white; a grim unfriendly sea. I glanced back at the leading edge of the wing and was relieved to observe that all the ice had gone, leaving the black rubber boots wet and shiny.
Down below the weather was not so bad as to be truly difficult, but it was not so good either. The last report had given two-six-zero twenty-five gusting thirty, five kilometres, eight oktas at 900 feet. The forecast seemed to suggest that conditions would not get much worse, which suited me!
As the illuminated figures on the DME ticked us through our 46th mile from the Sumburgh VOR I put my hands on the control column and pressed the red button on the left side of the yoke. On the centre pedestal a small green light labelled auto pilot engage went out. Of course I could have left it until much later, but an approach is an approach; a computer-brained autopilot does not need to practice - I do!
As we descended the sky became suddenly rough and the aircraft thumped and bumped through unseen waves of air that rose and fell like the wind-driven waves below us. Small aeroplanes reel and bounce in turbulence, while larger ones seem to punch their way through, absorbing a lot of the energy with a groan of protest and a shake that makes the instrument panel dance.
When the ADF needle began a slow swing to the left I turned, following it, my eyes flicking between the instruments; speed 140 knots, altitude 2,500 feet, rate of descent 600 feet a minute, angle of bank a shade too much, but then a vicious little bump knocked us almost level so there I was feeding in the bank again.
I rolled out on to a heading of 290, to allow for the forty degrees of crosswind, and I was gratified to see the ADF needle settle on to 297, only two degrees right of track; not bad!
"Speed below 147 knots, gear down and flap fifteen please," I said in a voice which sounded too relaxed to be thus without some effort. And my use of the word 'please' was more than just the simple oiling of my companion's sensibilities. Used there, as we bored through the murky belly of the cloud, it hinted of defiance. It seemed to suggest that even in that threatening sky, above the splintered sea and in that buffeting wind, normal social conventions prevailed. We tiny human beings were, after all, in full control of the situation. Please! It was a bit like whistling in the dark.
A series of rumbles, clonks and distant thumps told me that the gear had arrived even before the three green lights blinked on. But only the smallest trim change heralded the first stage of flap, and my eyes deliberately sought out the small flap gauge, mounted just below and to the right of the engine instruments, to see that they were indeed on their way down.
The next couple of minutes were spent striking a balance between the hesitant and sometimes ambiguous movements of the ADF needle and the effects of the gusting wind, but things were not going too badly. When we slipped through the tattered base of the cloud the runway was directly ahead, beyond the foaming white line where sea met land, across a bleak dark-green heath whereon stood the solitary hut which housed the NDB transmitter. There were the shining whites and reds of the PAPis, and there were the two lines of runway lights. To the right of the runway was the apron and a series of low white buildings dwarfed by a single grey hangar. I could see it all, and as we ravelled up the distance between ourselves and the airport I could dimly make out the hills beyond, rising darkly and merging with the grey sky. But for the moment I was only interested in the runway, with which I had an immediate appointment, for the runway was very short.
We bounced and slid down the invisible slope that ended at the runway threshold. The nose of the aircraft pointed towards the gently rising ground to the left of the runway, in order to keep us more-or-less on the centre-Iine. I was very conscious of speed, wanting neither too much nor too little. In the choppy air the airspeed needle made little twitches up and down the scale, and I watched it like a hawk.
"Speed below 120 knots, flaps, twenty-five and props, full-increase." The trim change was more noticeable this time, and as the condition levers went forward the propellers commenced an unsynchronised beat quite unlike the muted harmony they achieve in cruise. But it was the braking effect they produce in fine pitch that interested me. I let the speed bleed off to 100 knots and then stopped it in its tracks with a tiny change in attitude and an increase in power.
The runway was close now. I could see the flapping windsock clearly and the dull reflections of the runway lights on the wet tarmac. Then I asked for full flap. As the flaps travelled from 25 to 45 degrees with surprising rapidity the aircraft tried to balloon upwards, but I held it with a slight push forward on the control column.
Speed! I willed the speed back to 85 knots, just five knots above my Vat (threshold speed), and as the threshold slid beneath the nose I let the aircraft sink towards the numbers. Then everything happened at once. I leaned the left wing down and pushed in enough right rudder to point the nose straight down the centre-Iine. As the runway rose towards me I chopped all four power-Ievers to idle and flared in one rapid backward movement. The left wheel squeaked satisfyingly on to the tarmac, followed a second later by the right, I relaxed the back pressure to let the nose-wheel make contact, not hard, but firmly enough as my right hand began pulling the power levers through the gate into reverse, and my toes squeezed the brakes. Yet there was nothing dramatic about our roll-out. I did not need to use full reverse thrust, and the braking was moderate, nothing more. Even so. we did not use much runway.
"Locks!" The co-pilot leaned across to pull UD the substantial bar just ahead of the power levers, and the control column became solid and immovable. But my left hand was now on the ground steering control abeam my knee as i swung the aircraft on to the cramped apron.
We were at Unst in the Shetland Island, landing distance available 2,001 feet. I had just landed a four-engined fifty-one seat airliner on that runway using barely half that distance something that could not be done in many light twins. We had on board forty passengers and four crew; landing weight 40,350 pounds. If that seems impossible, then you obviously don't know the Dash 7.
The Dash 7 is not a pretty aircraft. I once heard someone say that it looks like a World War II bomber, an observation I cannot dismiss out of hand. Superficially the wing and engines are rather Lancaster-like, but the fuselage is absolutely standard modern turbo-prop, and the tall T -tail would not look amiss on a jet. The combination of these seemingly mis-matched components gives the Dash 7 a shape which is unmistakable, even to the most myopic aeroplane spotter.
The 7's cruising speed is in the modest 210 knot range; there are after all limits to the compromises that can be made between exceptional low-speed handling qualities and a high-speed cruise. Compared to its stablemate the Dash 8 it is less economical to operate, and yet ... accountants don't fly aeroplanes (thank goodness!), pilots do.
The Dash 7 is one of those increasingly rare transport aeroplanes that a pilot can puton like an old familiar jacket and fly. No pilot, however worn-out and disillusioned, could ever fail to immensely like the Dash 7. It is that kind of aeroplane.
There are only around one hundred examples of the type flying, and with the production line closed in favour of the Dash 8, it seems unlikely that any more will be built.
Most of those still working are used by airlines, oil companies, armed forces and charter companies that have one particular requirement: to take the biggest possible airborne load into the smallest available airport. The Dash 7 is often the only aeroplane equal to the task.
Its immense, hydraulically operated slotted flaps are the key to the Dash 7's outstanding STOL performance. They are almost full-span, only leaving room for tiny, rather ineffectual ailerons. At its maximum landing weight of 42,000 pounds the Dash 7's Vat is a mere 83 knots with 45 degrees of flap extended, decreasing to 71 knots at 32,000 pounds. These are light aircraft speeds for light aircraft runways, but the Dash 7 is not a light aircraft!
The flight deck is an orderly if rather crowded place The layout is conventional enough, a full set of flight instruments in front of each pilot, engine instruments in the middle. The centre pedestal carries the four power levers and four condition levers (combined propeller and fuel controls), as well as the trimmers, autopilot manual controls, and the weather radar and radio navaid boxes.
A large overhead panel houses all the electrical, pressurisation, fuel system, engine starting, and de-icing controls. The engine-fire warning and extinguisher switches are fitted on a rearward annexe to this panel.
The 84 caution and advisory lights are mounted forward of the overhead panel, just above the windscreen. By commercial aircraft standards the view from the front-end is very good, and there are two large side DV-windows, big enough to double as flight deck emergency exits.
The aircraft is fitted with flight directors of the crossed-needle type. The cross, which looks rather like the crossed needles of a conventional ILS instrument, makes demands by moving about the instrument face. The trick is to keep the aeroplane symbol in the centre of the cross with its wings on the horizontal needle. The autopilot and flight director are capable of doing all the usual clever things such as capturing pre-set levels, maintaining VOR radials, and flying a coupled ILS down to minima, including the 7 1/2 degrees ILS required by operations into London City Airport.
Two stages (25 degrees) of flaps are normally used for take-off, which can be a breathtaking affair for the uninitiated. It is not so much the speeds involved, which are modest enough, but the rapidity with which the aircraft accelerates, typically twelve seconds from brakes-off to rotate speed.
Keeping straight is no problem because in addition to the enormous rudder the nose-wheel is steerable, to a limited degree, directly through thr rudder pedals. The combination is more than enough to keep on the centre-Iine, even in a brisk crosswind.
A positive pull-back to eight degrees of pitch produces a firm step into the air with a Vr (rotate speed) of just 78 knots at the maximum take-off weight of 44,000 pounds. Acceleration to V2 (engine-out safety speed) is almost instantaneouus, and the initial climb is made at V2 plus ten knots until the gear is up and the flaps are retracted to fifteen degrees. The flaps are completely raised at 400 feet above ground level, when the speed is increased to 125 knots which gives a rate-of-climb comfortably in excess of 1,000 feet a minute. Once the aircraft is through the safety-height for terrain clearance an en-route climb speed of 150-170 knots is adopted until the cruising level is reached.
An engine failure on take-off is a bit of a non-event compared to the average light twin. The asymmetric forces can be quite easily held with rudder, and quickly trimmed out with the electrically operated trimmer, which feeds in a bias to the rudder in the appropriate direction. Meanwhile an auto-feather device senses the loss of power and dumps oil from the propeller governor to automatically feather the propeller. Two engines out on one side is rather less easy to manage, and in that situation you are definitely back to light-twin type asymmetric forces.
The Dash 7's controls are surprisingly light for a biggish aircraft. Because they must remain effective at quite low speeds the control surfaces are extremely generous - so generous that both the rudder and the roll control are iimited in cruise to prevent over-controlling.
In the case of the rudder an automatic stop reduces the range of rudder-pedal movement whenever the flaps are fully retracted. And roll control? Well, there is no need to limit the movement of the ailerons: on their own they provide, at best, a rather spongy response to control inputs.
The primary means of lateral comrol is by hydraulically operated roll-spoilers. There are two per wing and at low speeds each pair operates together to give extremely good rates of roll. Above 130 knots the outboard spoilers are disarmed, leaving the inboards to do the work in the increased airflow, without any noticeable reduction in effectiveness.
People are often intrigued by the idea of the 7 1/2 degrees ILS as flown by Dash 7s into London City Airport. Watching a steep approach in VMC it can seem impressive enough, but in IMC! Like all approaches it is just a question of getting nicely set up well in advance, not trying to catch up from behind. Even those who have never flown an ILS can appreciate that the beam width is getting narrower the closer you get to the runway. A normal three degrees glide-path allows a pilol reasonable time to settle down before the sensitive stage is reached. On a 7 1/2 degrees approach everything is condensed: you start at 'sensitive' and go on from there! The trick is to have the gear and 25 degrees of flap down, with the speed steady at 100 knots, before the glide-slope comes in. You earn your money for judging the right moment, but early is better than late. As the glide-slope needle starts its fairly rapid drop towards the centre of the instrument it is time to extend full flap and put the propellers into fine pitch. If you get it exactly right both those operations will be completed a couple of seconds before you reach the glide-path, so that by holding your altitude for a heartbeat or two you will start the approach with everything, including the speed, nicely organised. Thereafter it is just a matter of flying the needles accurately and keeping the speed at Vat plus five knots.
In all but the strongest wind the rate of descent will be in the region of 1,000 feet a minute. While the aircraft is resilient enough to accept the sort of landing likely to result from a late flare with a high rate-of-descent, your pride will probably suffer severe bruising! Kinder, then, to feed on a bit of power just before you flare and flatten out the approach slightly before you start to hold off.
The Dash 7 can be a stiff-Iegged bird to land when full-flap is down and even the most experienced pilot will occasionally arrive with a teeth-rattling clonk! On the whole fortune tends to favour those who have the courage of their convictions and hold off positively while dispensing quite rapidly with the power. 'Feeling' for a smooth touch-down often has the opposite effect!
In turbo-prop terms the Dash 7 is a big, solid, strong aeroplane; a serious workhorse able to do all that is reasonably required of it, plus a bit more. See one parked among its peers and it belongs. See one parked alongside a row of light twins and it looks serious, aloof, all grown up. Although the Dash 7 is not a light aircraft, it handles like one and if it could sing a song to those light twins what would it be? How about, 'Anything you can do I can do better. .?