An Aviation Image from aviationhumor.net.
"You Are Never Too Old"
This image was just too good not to share.
An Aviation Image from aviationhumor.net.
"You Are Never Too Old"
This image was just too good not to share.
"The Value of Currency."
By Owen Zupp
So often the issue of experience is paramount in a pilot’s career. Total time, experience on type and multi-engine hours are all barometers used to assess a pilot’s possible expertise. While a valid means of measurement in one sense, an equally critical aspect in the present tense is the matter of currency.
Keeping it Relevant.
The log book tells the story of our journey along the path of aviation. We carefully log each hour and eventually the next personal goal draws nearer. Ultimately when standards are met and qualifications are gained the log book continues to tick over, day by day, and reflects the overall experience of the pilot.
Yet within the log book’s story are a number of smaller chapters. They relate not only how much experience was gained, but the nature of the flight and the time that has lapsed since. This gives weight to the relevance of the experience. 10,000 hours in command of a Boeing 747 won’t necessarily equate to a safe crop-dusting pilot weaving amongst the trees and power lines. Nor will a little crop-dusting experience in the distant past ready a pilot to depart today for a low level spraying run without some type of refresher training.
Within commercial operations a thorough record is kept of the last instrument approach, night landing and so on to meet the regulatory requirements. By virtue of the full time nature of the employment, recency is not generally an issue. Even so, in the summer months with long days, night landings can prove elusive and for Check Captains confined to simulators and observing from ‘jump seats’, actually flying can be of a premium. Even seasoned campaigners need to be wary of a lack of currency.
It’s not Easy.
Flight time needs to be relevant and this can at times provide a real challenge. With the cost of flying providing a challenge at the best of times, it is genuinely difficult for the private pilot to keep their ‘hand in’ at all. The vast majority of licensed private pilots struggle to fly 50 hours per annum, or less than an hour each week. As such, when they do become airborne, it is vital that the maximum value is extracted from the time aloft.
While the minimum requirements may call three take-offs and landings every 90 days, is this really adequate? Furthermore, this may only be a requirement for the carriage of passengers. And what of the prevailing conditions? There are no stipulations regarding crosswinds, controlled airspace or runway length. A pilot may have satisfied the minimum requirements at a home port before launching solo through controlled airspace to a short, unsealed strip with a howling crosswind. Sure, a flight school may have additional requirements for hiring an aircraft, but what about the private owner? There is legal and then there is prudent.
Having conducted a number of Biennial Flight Reviews (BFR) in the past, it can be quite interesting to see the varying standards of operation amongst pilots. However, the core problem was often an issue of recency and sheer lack of practise. The pilots had managed to maintain their 3 take-offs and landings, but little else. There had been no practised forced landings, go-arounds, flapless or short field operations since their last review; and it showed.
As I have said, I sympathise and can even empathise with the reality of economics that can make every minute aloft financially painful; however, there is still a duty of care to ourselves, our passengers, other airspace users and those folks whose roofs we fly over. As such, we must all shoulder the responsibility and make every effort to be as proficient as possible before we utter the words, “Clear Prop!”
Putting a Plan in Place.
A successful flight at all levels of aviation is the culmination of not only manipulative skills but sound planning. Frequently, the level of preparation I have witnessed for private pilot licence flight tests has been phenomenal, with pre-flight planning endeavouring to account for any number of variables that may surface along the way. Unfortunately, once the licence has been gained that state of readiness is often eroded by a combination of factors ranging from currency to complacency.
While ‘risk management’ is in danger of becoming a trendy catch-cry, it is actually a worthy way of thinking about staying safe in the face of infrequent flying. Well in advance of a flight, sit back in the comfort of your home and honestly think what aspects of the sortie give you a sense of unease or trepidation. What bad experiences have you had previously? Were you confronted with a late runway change, or flared far too high? Were you high on approach or did you get lost on some poorly signed taxiways? These areas can be a great place to start.....
Check back soon for the conclusion to "The Value of Currency."
A RAAF CA-18 Mustang makes its final approach under the keen eyes of the growing crowd.
Check back soon for the next "Five Tips" article. This time we look at undertaking flight tests and upgrading your licence.
"Taking Flight" (Final Part)
To Go or Not to Go?
Airline category aircraft have specific data relating to the point at which a take-off can be safely continued in the case of an engine failure. Similarly, beyond a certain speed, the decision to reject a take-off and remain on the ground exposes the aircraft to the real danger of over-running the runway. While the decision to go, or not to go, may be straightforward for such things as an engine failure in a Cessna 152, matters are not always so black and white.
Light aircraft don’t generally possess a “go or no-go” speed, but there are incidents that may take place on the take-off roll that are not necessarily an emergency, but will require attention at some point. The challenge then is to ascertain what action will present the greatest risk; continuing to fly or over-running the runway. Each decision will be different for each pilot, runway and aircraft and even the stage of the take-off. However, it is worth dedicating some thought to the scenarios before they ever occur.
One of the most common incidents is a door coming open just upon rotation on take-off. For all the associated noise of rushing air and startled passengers, generally the door will only pop open a small amount and be kept quite flush by the relative airflow. On a 3 kilometre international runway, you may decide to re-land ahead, but on a short remote airstrip with a precipitous drop off the far end, you may decide to continue. Additionally, the point of decision may be indicated by a physical feature along the runway indicating the distance remaining, or may be as simple as actually becoming airborne is the cue to continue. Each day will be different, but a plan in advance is well worth having.
A door opening is just one such scenario. Poor acceleration on the take-off roll, a realisation of an incorrect flap setting or a seat sliding back prior to lift-off are all events that are best considered before they strike. The very best technique is to guard against such eventualities with good airmanship and sound checklist discipline.
Taken for Granted.
In many ways, the take-off manoeuvre is a straightforward exercise of aircraft control. However, there are ample opportunities for this critical phase of flight to turn sour. The seat belt hanging out of the aeroplane and doors popping open on take-off have both been quoted as distracting occurrences on take-off. Wrong trim settings, incorrect flap selection and an unsecured seat sliding back are potentially fatal oversights in the take-off process. A misidentification of the correct runway has seen a number of accidents occur, particularly in low visibility situations, while fatal accidents have stemmed from attempted take-offs on occupied runways. Who can forget the collision of the KLM and Pan Am 747s at Teneriffe in 1977!
Our best defence against is often in our own hands. Respect the performance limitations of the aeroplane, follow standard operating procedures and conduct checklists in a thorough, measured manner. Even so, there are additional ‘safety filters’ we can introduce to our flying; the engine out and departure planning is one such measure. Prior to lining up, we can verify that we are at the correct holding point before entering the runway. Additionally, a final assessment of the wind, local weather and terrain is timely. Consciously look for aircraft before lining up and be aware of how design features such as a high wing may impede the lookout. Once aligned, our check of the runway direction against the compass is another verification of the runway.
Sometimes, there are final checks that vary from pilot to pilot just before they start the take-off roll. It may be a push back upon the seat to verify that it is absolutely locked in. For others a last look at ‘Fuel, Flap and Trim’ may be seen as worthwhile. However, once the take-off has commenced, the focus must be purely on the manoeuvre as it has been trained for. If it hasn’t been checked now, it’s not going to be. If it is that critical, this may be one of the reasons for which you decide to reject the take-off if it is safe to do so.
We have said previously that with so much emphasis on the approach and landing phase of flight, the humble take-off is frequently overlooked. Often perceived as simply lining up, pushing the levers forward and pulling back when the time is right, the take-off is actually a very critical phase of each and every flight.
We have seen that to the contrary, a truly safely executed take-off is one that has catered for a series of events that hopefully never occur. Furthermore, the variables that are presented on each occasion need to be considered for their impact upon the take-off manoeuvre before we start to roll down the runway. Only when man and machine are truly ready should they venture into the sky above. When prepared, the take-off can then safely open the door to the wonder of taking flight.
A QANTAS Boeing 737 taxies in to the backdrop of a setting sun.
‘Taking Flight’ (Part Three)
‘Taking Flight’ (Part Two) looked at the preparations and execution of getting airborne. However, there are variables outside of the pilot’s hands that nevertheless must be considered and countered to ensure a safe take-off. From environmental effects to emergencies, we will now consider subtle safety strategies to counter these different conditions and see that there is more than one way to take flight.
The Powers That Be.
Whether man takes to the land, sea or sky he will always be at the mercy of the elements to some degree. They can be seen as a threat or a challenge, but either way nature is an inescapable aspect of aviation. From crosswinds and climate to wet runways and windshear, the range of conditions are as diverse as the planet itself.
There will be days when those conditions exceed the performance of the aeroplane or our own level of skill and the prudent choice in these situations is to stay on the ground and fly another day. However, more frequently the elements will be within the grasp of both crew and machine, so due consideration should be given before advancing the levers and accelerating down the runway.
The wind can be our friend when it is blowing straight onto our nose for take-off. Reducing the ground roll and increasing the angle of climb and obstacle clearance, a headwind is the ideal ally provided by nature. Unfortunately, pressure systems, noise abatement procedures and local topography do not always ensure that the wind direction is our friend. At times it will blow from abeam and present a challenging crosswind, while a wind from behind will penalise performance in the manner that a headwind can aid it. Tailwinds will both extend the ground roll and erode the angle of climb. To this end it is critical that take-off performance charts are consulted regarding the take-off distance required with a tailwind, while the aircraft limitations will generally state a maximum tailwind component regardless of the amount of available runway.
The major consideration in the event of a crosswind is the issue of directional control. The ‘downwind’ wing is shielded by the fuselage to a degree, while conversely the ‘upwind’ wing is in receipt of greater air flow, encouraging it to fly. Consequently, the upwind wing needs to be held on the runway during the take-off roll with the appropriate use of aileron. Compounding this directional issue is the effect of the crosswind on the aircraft’s fuselage and the tendency for the aeroplane to ‘weather-cock’ into wind. Through a combination of control inputs, which may actually see rudder and aileron in opposition, the goal is to maintain that centre-line during the take-off roll. Once airborne, the aim is to smoothly return the controls to the balanced inputs required for the climb out as the aircraft is now free to weather-cock into wind. The challenge then is to fly the extended centreline without being blown downwind.
Temperature is another environmental consideration for the take-off. Warmer temperatures can be detrimental to the take-off on a number of counts. Firstly, the heated air is less dense and stifles the performance of the aerofoil to lift the aircraft from the runway. So much so, that for every degree Celsius above ISA, it is equivalent to raising the airfield a further 120 feet above sea level. For instance, a 30 degree day would equate to an airfield at 1800’ higher than its true elevation. Further to this, the propeller is less efficient in the thinner air and the engine suffers from reduced volumetric efficiency with a corresponding drop in power output. All of this equates to a longer ground run and reduced climb performance which once again needs to be verified preflight in the aircraft’s performance manuals. With humidity also affecting air density and take-off performance, the old catch-cry to be wary when conditions are “Hot, High or Humid” makes very good sense.
Conversely, cold climates may equate to better take-off performance due to their positive effect on air density. In these regions, the greater threat lies in the presence of frost, ice or snow. These forms of moisture can severely destroy the lift characteristics of an aerofoil, so as always a thorough preflight of the aircraft is essential, with increased vigilance towards contaminated surfaces. Furthermore, when present upon the runway, visible moisture may not only retard the take-off acceleration, but risk being ingested into engines as it is thrown up by the undercarriage.
The surface does not need to be contaminated by ice or snow to hamper the take-off roll. Sometimes it is the natural surface of the runway that proves to be an effective retardant in the form of long grass or desert sands. Obviously, the presence of water will compound the issue, but unkempt grass can provide quite a surprise to the student raised solely on black asphalt and painted centre-lines. Sometimes the Flight Manual will recommend a ‘soft field’ technique which advocates the use of a higher flap setting to allow the aircraft to become airborne at a lesser speed. However, the catch comes after take-off when the climb performance is degraded by the extra flap extension, so ensure that obstacle clearance is not a particular issue.
The good news is that environmental factors have been around since the Wright Brothers and much has been learnt in the years in between. Consequently, aircraft performance manuals cater for most situations and if you abide by the book figures, you should be covered. If the prevailing conditions are so unique that they are not catered for, or should they exceed the published limits, then the only safe option is to stay on the ground and wait for conditions to improve.
The Big Bang. (...and sometimes not)
An engine failure on take-off is regarded as one of the most critical situations a pilot can encounter. In a single-engined aircraft, gravity and inertia become the powerplant and only limited options and time lay ahead. In a multi-engine aircraft, the outlook may be more promising if the failed engine can be secured and the aircraft is able to fly away to a safe altitude. I emphasise ‘may’ as only the foolhardy believe that a light twin’s second engine is always a guarantee of climb performance.
Whether in a single or a twin, an ‘escape plan’ should be formulated in the event of an engine failure. What is the terrain situation on upwind? Are there parallel runway operations? Are there forced landing fields or a nearby airport? If I am struggling to maintain height in a twin, at what height will I start to turn back towards the field and will I turn left or right? Clarifying these issues prior to take-off is invaluable and may in fact dictate your departure plan with everything working. An early or delayed crosswind turn in a single may avoid some nasty terrain should the engine go silent. Better safe than sorry.
Furthermore, it would be remiss to consider engine failures without remembering that they are not always a cut and dried ‘bang’ followed by silence. It may only be a partial failure, or even sound a whole lot worse than it is. The repeat offenders of a blown tyre on take-off or a seat belt outside the door banging on the fuselage have both led pilots to believe that the aircraft engine was about to self destruct. No matter how much noise or vibration may be present, verify the aircraft performance. If the aircraft is still performing satisfactorily, don’t rush into anything, but keep climbing for precious altitude where you have options and time to carefully analyse the problem.
Check back soon for the conclusion of 'Taking Flight'.
Sunset at 38,000 Feet.
"Taking Flight" (Part Two)
For many of us, the hardest part of the day is opening our eyes, throwing our legs over the side of the bed and starting the day. Our mind hasn’t quite snapped out of its slumber and our bodies are not yet fully prepared for motion. It won’t take much to get going, but there is that short lag in the lead up to the day. For an aircraft, leaping into the sky is not too dissimilar.
As the aircraft sits in the run-up bay, it may only be minutes since it too has ‘woken it up’. Its temperatures and pressures may be sitting in the lower bands of the dials and its trim setting, flaps and fuel selections may be left over from the night before. It would be pointless and foolhardy to open the throttles in this state and expect with full assurance that the aircraft will perform soundly and safely take us aloft. To this end, the pre take-off sequences are a vital aspect of flight.
Every company and individual will have their own order of events; just as long as there is an order. It will comprise of such components as checklists, engine run-ups and briefing (see "Well Chosen Words") to ensure that pilot and aeroplane are both ready for the flight ahead and in particular the critical take-off manoeuvre that is now imminent. It is important not to rush this process as too often a simple oversight of fuel selection, an unsecured seat or flap setting has brought an otherwise serviceable aeroplane to grief.
This is the last point where the security of the earth still offers limitless options in a comfortable environment. Use the pre-take-off sequences, and a short pause afterwards, to ensure that you are absolutely satisfied that all issues have been addressed prior to take-off. It is often said that it is better to be on the ground wishing that you were in the air, than the other way around. Take a moment prior to each take-off to remember this.
With all bases covered and a serviceable aeroplane ready to go, it’s time to take flight.
Approaching the holding point, cast one eye to the sky to gain an appreciation of the traffic situation, local weather and anything of interest such as flocks of birds. Confirm that the windsock reflects what you have planned upon and consider how it may affect your take-off. In other words, start gaining a deeper appreciation of the airborne environment that you are about to launch into.
Even with a clearance at a controlled airport, take a good look in both directions before lining up as even Air Traffic Controllers and other pilots can make mistakes. Having attended to the housekeeping of external lights, transponder verifying that you are on the correct runway, the aircraft is now lined up on the centre-line and awaiting for the actions that will convert it from an earthbound misfit to a gravity defying machine.
Everything about the take-off should be smooth. From the gradual advancement of power, to directional control and rotation, there should be a degree of ease in every motion. This is not only sound aircraft handling, but offers a greater opportunity to detect any abnormalities that may arise. While the eyes are predominantly outside, there should be a brief scan of the engine instruments to check for normal indications, noting the RPM to confirm that the required power is being produced. For turbocharged engines, there is always the potential for an ‘over boost’ situation as well. When all is confirmed to be in order, the scan inside should mainly be seeking the critical speeds as the take-off develops.
If you routinely fly the same aeroplane, there may be a gross error check of how much time or how far down the runway it takes to accelerate to a certain speed. This can provide an early warning to a poorly performing engine or a significantly contaminated runway surface.
The Take Off Safety Speed (TOSS) provides a margin over the stall speed and is a minimum speed for lifting off and flying away safely. It may differ from the recommended lift off speed at which the pilot rotates the aircraft into the air, but is always worth committing to memory as a critical speed. Coaxing an aircraft into the air prematurely can leave an aircraft ‘mushing’ along in ground effect with no chance of actually climbing away. Furthermore, it cannot be emphasised enough to follow the manufacturer’s recommended take-off technique as aircraft can have their own idiosyncrasies.
The actually rotation of the aircraft into the air should be smooth and is often quoted as being around 3 degrees per second. Whatever the rate is, the aircraft should not be ‘yanked’ abruptly into the air as this introduces a series of potential issues from tail-strikes to over-rotation and the bleeding of speed at a critical time.
Eased into the air at the correct speed, the take-off will provide the aircraft with the best available performance. In real terms this equates to safety margins on minimum speeds and optimum obstacle clearance at the far end. From there the task involves establishing a safe climb-out and configuring the aeroplane for departure. Just as you handle the aeroplane with ease, approach this task with a measured technique.
What’s the Hurry?
Once airborne, the job is far from over. Vigilance remains an important task and should be spread between flying the aircraft accurately, monitoring aircraft performance, looking out for traffic and being at the ready for the dreaded engine failure after take-off. By virtue of this, the pilot on ‘climb out’ is quite occupied and the workload is high. Throw into the mix a radio transmission or two at an unfamiliar airfield and it can become downright busy.
To this end, there is no hurry to attend to secondary tasks. Jet airliners normally climb to 1,000 feet before they consider reducing power and this isn’t a bad policy when the aircraft is equipped with prop levers either. Why hurriedly turn off auxiliary fuel pumps or retract the take-off flaps unless there is a chance of exceeding their extension speed? Climb the aircraft away from the ground and then begin to converting it into the cruise climb.
There would undoubtedly be a great deal of regret if the wrong switch was actioned or an actual failure took place as the fuel boost pump was flicked off at 300’. After all, it is there to back up the engine driven pump in critical phases and normally, if the engine genuinely fails, one of the first actions is to switch it on. So just leave it alone. And that is not to mention the fact that actioning switches and confirming indications draws the eyes inside the cockpit when they should either be outside or focussed on an instrument scan if in IMC.
In a similar fashion, when a light aircraft with a retractable undercarriage takes off at a major airport with 3,500m of runway, there’s no urgency to retract the undercarriage. If the engine stops, you’re landing ahead so you might as well already have the gear out and not sweat on it extending in time in an emergency. A number of pilots call “runway away, gear away” as the upwind threshold disappears under the nose.
Like the take-off roll and rotation, the climb out and re-configuration should be done with method and forethought, not haste. Consider the variables well before you advance the throttles and the departure will unfold far more smoothly. Aircraft should be flown and not merely pushed around without giving consideration to handling and consequences. It is just one more area of airmanship that separates flight from so many other activities.
The take-off is a relatively simple manoeuvre which constitutes a critical phase of flight. It is one of those aspects of aircraft handling that is easy to do, but easy to do badly. What further compounds the challenge are the seemingly endless variables that can impact upon the take-off sequence.
In "Taking Flight" (Part Three), we will examine a range of normal conditions and dire emergencies that can directly affect the way in which an aircraft takes to the air. From subtle safety strategies to countering different conditions we will see that there is more than one way to take flight.
Check back here soon for Part Three of "Taking Flight."
It's a sad day here at the aviation blog.
Yesterday I received the news that a friend had lost his life in an aircraft accident. He was an experienced pilot and an absolute gentleman.
As the details of the accident filtered out through an unreliable media, I chose to reflect on some good memories and interesting conversations that we'd had in those long hours on the darkened flight deck.
My thoughts are with his family at this time. As I said, he was a true gentleman.
Rest in peace, mate.
Over recent months tragic news seems to have become all too frequent for the aviation community. While on the other side of the Indian Ocean the loss of the two Albatross aircraft dealt a single massive blow, here a series of accidents in just a few days has further added to the count. The national broadcaster’s senior helicopter pilot and crew were lost, just as the news of an ill-fated mercy flight filtered down the wire. Only hours later, a senior sports pilot and his passenger went missing with a fatal outcome. The terrible loss of life in New Zealand when a hot air balloon was destroyed and only this week, a Tiger Moth crash saw the passing of John Fisher; a man who had once flown his Tiger from the UK to raise funds for charity. In the cruellest manner, it seemed we were all reminded that tragedy is the ever-present companion in the skies we seek to transit.
As the son of a fighter pilot who'd flown in combat, I had grown up around the potentially fatal nature of aviation. As I flicked enthusiastically through photo albums of fading photographs of fast jets, my father would answer my questions in an even tone. Often my enquiries with reference to individuals was met with, “He got clobbered by ground fire near Haeju”, or “I think he put a Mirage in off the coast during a training exercise”. Their young faces beneath flying helmets still stare back at me so many years later.
My own first encounter with the harsh lessons of aviation started as a student pilot. Still a paramedic by trade, I stood at the Royal Aero Club counter as the crash horn sounded and the ominous black, oily plume rose from beyond the runway’s end. Off duty, I drove my car the short distance around the airfield perimeter and entered the factory where the Cherokee Six had plunged vertically through the roof. One burnt survivor has been thrown onto the rooftop, while I dragged another from the smoke-filled building. Four remained in the wreck, still strapped into their seats; lifeless. Any complacency about aviation that youth may have been tempted to bestow on me was nullified at that very moment.
In the losses of recent times, as is so often the case, there are not necessarily any common themes. Each was in a different category of aircraft, with the weather varying from despicable to fine and clear. The pilots ranged vastly in experience and their operations covered the spectrum from private flying to commercial aviation. The only shared trait seemed to be the tragic outcome.
I flicked through the various news reports with a strong dose of suspicion, borne of decades reading of ill-informed, sensationalist reporting. Details seemed to change by the hour and rumours took on the status of fact until the next piece of hearsay could be generated in the public domain. What could not be disputed was life-altering impact of these accidents upon so many. To such a backdrop, one by one I recalled the faces of those that I had seen lost at the brutal edge of aviation. As I penned each name, the sobering truth was rammed home to me; no one is immune.
The list of names was far longer than I had anticipated. They ranged from pilots with whom I had shared a meal and conversation, to close friends and work colleagues. Nearly all of them were commercial pilots eking out a living in general aviation, though some had also been taken pursuing their passion just for the love of it. Some were just starting their journey, excited at their first gainful employment and some were experienced mentors in the service of the national aviation regulator.
One by one I recalled their faces. The ‘old hand’ Bill whose ultimate oversight in forty years of safe flying was not spotting the glider that sheared off his Bonanza’s tailplane. And Brinley, celebrating at the local restaurant at the news he’d secured a position with an airline only to perish nights later, circling into a black hole in rural Australia in the foulest of weather. Trevor, whose single-engined fish spotting aircraft had force landed at dusk into the frigid waters only to survive the impact, but not the swim to shore. Alan and Peter, who had been searching for another aeroplane when their Cessna’s had engine failed over inhospitable terrain. Fernando, who descended gently into the ground in the wee hours with a full load in his Beechcraft. My fellow freight pilots who had been lost within a couple of months in a bleak, wet winter of low cloud and icing levels. And my close friend who’d tried one too many hair-raising flying feats at too low an altitude, only to pancake into the rising terrain. On and on the list continued as face after face stared back at me.
Admittedly, there were those who had been sticking their neck out further than the rules and common sense would advise. But for most it was simply a case of the odds stacking up against them in a series a compounding smaller events; the classic ‘Swiss Cheese’ model of Dr. James Reason. For a few it was the simple bad luck scenario of wrong place-wrong time. Universally, however, they are all still with me; even though I had not thought of many in recent years. They are with me as I flight plan and as I retract the gear. They are with me as the day becomes night and as the weather turns dark and walls of water confront me. They are with me always.
They are not evil spectres awaiting my demise, they are those who have gone before and paid the ultimate price. They paid for their harsh lessons with their lives and I am now the benefactor of their loss. In many ways, I owe them for the joy I have experienced in the skies above. They may have gone before, but they have stayed behind to tell me when enough is enough and when danger is lurking. They are there when the hair stands up on the back of my neck. They level the playing field and stand on the kerb whenever the temptation to cut a corner may exist.
They were acquaintances, colleagues and close friends who lived and breathed for aviation. I count myself as fortunate to have thus far safely encountered my way, but this is not an automatic right. It requires an ongoing commitment to safety and discipline in all circumstances and anything less is to dishonour those who have sacrificed so much. We call the skies our home and it is not a dangerous place to encounter. However, as those who have been lost recently and in the distant past can attest, that aviation can be very unforgiving.
Clear skies, mate.
Dusk at Caboolture.
"Taking Flight." (Part One)
With so much emphasis on the approach and landing phase of flight, the humble take-off is frequently overlooked. Often perceived as simply lining up, pushing the levers forward and pulling back when the time is right, the take off is actually a very critical phase of each and every flight.
Surface to Air.
There is nothing quite like that moment when the earth falls away from the wheels and the earthbound restraints transition into freedom in all three dimensions. From the initial surge of power to the nose pointing skyward, guiding the aircraft back to its natural habitat, this is when flight becomes a reality. This is the take-off and for all its majesty, it is also a potentially vulnerable time for man and machine.
Like landing, it is a manoeuvre conducted at ground level where there is little time and altitude for forgiveness. It is susceptible to all manner of variables; environmental, aerodynamic and human in origin. Accordingly, like any phase of flight, the take-off should be given the respect and consideration it deserves. Attempts to rush it can at the very least result in poor handling and at worst leave the aircraft exposed to all manner of lethal variables.
Fundamentally, aircraft are not designed for ground operations, they are meant to fly. As such, designers endeavour to build an undercarriage that will sustain the impact of landing, maintain a straight line at high speed, taxi at slow speeds and offer up the lowest possible weight penalty in the process. Similarly, the wing is meant to fly and generally fly fast. The slow speed envelope is recognised as a necessary evil in transitioning the aeroplane to and from flight, so often aerodynamic devices on the leading and trailing edges are added to facilitate this. Yet on take-off, the undercarriage will be asked to absorb the shock and slipperiness of all manner of surfaces and we will reconfigure the wing so it will fly at speeds that it would really prefer not to.
At the helm sits the pilot who has hopefully both configured the aircraft correctly and considered a myriad of possible eventualities. Should the take-off go awry, decisions may need to be made in a split second and yet enacted with a seemingly unrushed, efficient methodology. As with so many aspects of aviation, the result of thorough preparation is often a routine non-event. Take-offs are no exception to this rule.
In its most basic form, the purpose of the take off is to transition the aircraft safely from the ground into the air. It is not to be considered purely as the instant of lift-off, for there are several components of the take-off both preceding this moment and following it. In fact, the take-off can really be considered as commencing with its planning in terms of weight and balance, performance data and the ambient conditions. Likewise, the take-off can be thought of becoming a ‘climb’ only when the aircraft is reconfigured and at a safe altitude. This may involve reducing power and the retraction of flaps and undercarriage, or simply extinguishing lights and selecting the fuel pump off; it will vary from type to type and even departure to departure.
The take-off is virtually a ‘blink’ in the overall duration of a flight, but the degree of preparation isn’t a function of time. Just ask an Olympic sprinter or world class photographer. Safely executing a take-off is a combination of consideration and physical execution and in ‘Taking Flight’, both will be treated with equal respect. However, to start, let’s review what is actually involved in taking our aircraft from the runway to the sky.
A Numbers Game.
Before the park brake is even released, the ability of the aircraft to physically perform the take-off manoeuvre must be verified. This is a function of numerous factors including aircraft weight, payload, centre of gravity, the runway environment and ambient conditions. Each of these variables plays a significant role in their own way and to overlook any aspect can be fraught with danger.
In most cases, the individual approved aircraft Flight Manual is the defining document in matters of performance. Some larger operators may have an entire approved loading system that is a stand-alone manual or in modern times, part of the Electronic Flight Bag. Whatever the means, there is always a valid method to calculate the limits of an aircraft’s performance in executing a take-off.
The take-off must be able to accelerate and climb away at a safe speed with adequate obstacle clearance in the distance available. In the case of multi-engine aircraft there will also be a need to climb away with one engine inoperative and for higher category aircraft, the ‘stop-go’ scenario, amongst others, becomes a performance dictator. Fortunately, the hard work has been done by test pilots and performance engineers when the aircraft is certified, so the preflight process is a case of arithmetical gymnastics rather than ‘trial and error’ destructive testing off the end of the runway.
Typically with most GA piston powered aeroplanes, the number of seats doesn’t directly reflect the everyday uplift of the aircraft. You may well plan to take 4 people aloft in a Piper Cherokee 140, but that will rule out anything near full fuel tanks. To this end, performance calculations often require the pilot to make do with the best legal solution. If a full load of passengers is a requirement on a cross country flight, the fuel load may need to be reduced and additional refuelling stops must be planned. It will always be a combination of aircraft weight, payload, people and fuel without exceeding any limits. If the numbers still don’t work then it might be time to consider upgrading to a larger, more powerful aeroplane to meet your needs.
Further complicating the matter is that even if the total weight to be uplifted is legal, it must also be loaded in a manner that the aircraft remains ‘balanced’. Like a see-saw, the aircraft can tend to pitch nose up or down depending on how the aircraft is loaded in relation to its centre of gravity. Too far forward and the nose may not want to lift off on take-off, too far to the rear and the nose may just keeping pitching skyward after rotation until the aircraft stalls. To avoid the imbalance of an aircraft leading to disastrous controllability issues, a graphical representation or tabular calculation of the limits fore and aft is used. Calculations of load distribution must have the weight and balance of the aeroplane falling within the safe region known as the Centre of Gravity ‘envelope’. Bearing in mind that this position may also change enroute as fuel is burned.
So your aircraft is loaded to below its maximum limit with fuel, folks and freight distributed in a balanced manner. The next piece of the puzzle relates to the runway environment. Is it long enough? Is the surface long, wet grass which will impede acceleration? Is it sloping uphill? What is the current temperature and prevailing winds? These considerations must also be assessed when using the performance charts to verify that the available runway is ample and suitable for take-off.
Only when the aircraft performance data has been calculated with respect to weight and balance and airfield limitations can a take-off be legally and safely executed. Accident investigations are littered with instances where pilots either overlooked or chose to ignore the performance envelopes of their aircraft. Take the time to do the numbers and peace of mind will inevitably follow.
Check back here soon for "Taking Flight" (Part Two).