Three de Havilland Tiger Moths put on a show.
Three de Havilland Tiger Moths put on a show.
The view through the 'Head-Up Guidance System' (HGS) of the Boeing 737-800.
Image by Steve Ruttley.
Check back here for the upcoming 'Blog Post' on Head Up Displays.
Hi All, here's something a little different today.....
The De Havilland aircraft company had a fine tradition of civilian training and touring aircraft prior to the outbreak of World War Two. From Humming Birds and Hornet Moths to Dragons and Albatross, the British company produced a vast range of machines. At the upper end of the speed spectrum was the twin-engined monoplane, the DH88 Comet. Manufactured from wood, the Comet blew away the competition in the 1934 MacRobertson Air Race from the UK to Australia, though just as significantly, it planted the seed for a revolutionary military aeroplane. The DH 98 Mosquito.
The Mosquito was originally conceived as a high speed unarmed bomber. In 1940 with Great Britain facing its darkest hour and a shortage of resources, it needed aircraft and it needed them quickly. Though the Air Ministry had some reservations about the unarmed aspect of the design, it could not argue with de Havilland’s expertise in wooden aircraft production techniques. Additionally, the fact that its construction called for minimal amounts of treasured metal resources offered up a viable alternative.
After a series of changes in the aircraft’s perceived role, the original order was modified to a requirement for 20 bombers and 30 fighters. The prototype initially built in a hangar disguised as a barn at the home of de Havilland, Hatfield. It narrowly missed being destroyed during a successful Luftwaffe bombing raid on Hatfield that did spell the end of a number of materials and over twenty people. However, the Mosquito survived and undertook its maiden test flight in November of 1940 at the hands of Geoffrey de Havilland’s son of the same name. During the subsequent trials the Mosquito’s speed established it as the fastest combat aircraft on either side of the conflict; a title it held for the next two years.
Into the Fray.
The Mosquito’s first operational sorties were in the role of Photo Reconnaissance (PR) in August 1941, a task it was ideally suited to with its high speed. Early in 1942, the aircraft began to see service as fighters and bombers. The Mosquito had far exceeded the original specifications and through minor modifications was able to carry 500 pound bombs in place of the originally planned 250 pounders. The first bombing raid was a daylight strike on Cologne after a “1000 bomber” raid had taken place the previous evening.
The versatility of the Mosquito became apparent and aside from being a fighter, bomber and photo recon aircraft, it successfully served as successful night-fighter and even participated in the “Hunter/Killer’ pairing of Turbinlite operations. The Mosquito was also extensively used in the precision-navigation role of ‘Pathfinder’ where it would fly in advance of the main bomber force to mark the target with incendiary ordinance. BOAC (the forerunner to British Airways) even used civilian registered Mosquitoes during the war to run the gauntlet between Britain and neutral Sweden on a regular air service. There seemed very little that the Mosquito could not do.
In its time, the Mosquito was called upon to fill some rather niche roles that have gone down in folklore. Two of these were 618 Squadron’s use of the bouncing bomb ‘Highball’ and the breaching of prison walls in ‘Operation Jericho’.
While much has been written of Barnes Wallis’ bouncing bomb and the Dambusters raid on the Ruhr Dams, there was an alternate deployment of the bouncing bomb planned for use by the Mosquito. This version of the bomb was known as ‘Highball’ and while the Dambusters used a cylindrical style bomb, ‘Highball’ was far more spherical. Also conducted under a great veil of secrecy, 618 Squadron was tasked with using the bomb in an anti-shipping role with its number one priority the sinking of the German battleship the Tirpitz. Unfortunately, despite all of the effort and training, 618 Squadron never had a shot at the Tirpitz and eventually the squadron was deployed elsewhere.
A task for the Mosquito that did see notable fruition was ‘Operation Jericho’. Conceived in 1943, this mission involved an attack on the Amiens Prison in France which was holding amongst others, numerous members of the French Resistance who were scheduled to be executed. The daring low level attack took place on the 18th February 1944 and included squadrons from the RAF, RAAF and RNZAF. Its plan was to destroy the prison walls to facilitate the escape of the inmates, with an alternate plan of destroying the prison outright should this fail. It did not, and while there was loss of life, hundreds of prisoners were able to escape.
To quote specifications for the Mosquito is akin to comparing racehorses; there are so many types and so many variables.
In essence, the Mosquito was a twin-engined combat aircraft of primarily wooden construction. It was operated by two crew, including the pilot, and whether the second crewman was a navigator, bomb aimer or radar operator was dependent upon its designated role.
Powered by two Rolls Royce Merlin engines, it could carry nearly two tonnes of bombs deep into the heart of Germany. As a fighter it could carry 4 × 20 mm Hispano cannons in the fuselage and 4 × 7.7 mm (.303) Browning machine guns in the nose. Some photo reconnaissance versions had a service ceiling of 40,000 feet and a number of marques had a top speed in excess of 400 mph.
Ultimately, nearly 8,000 Mosquitoes were built and of these around 6,700 were delivered in wartime. As an aircraft it was not purely versatile, it was truly prolific as well.
As with all types, a number of Mosquitoes met ignominious ends on scrap heaps at the end of the war. However, several models survived and the Mosquito production line remained open until 1950. They saw service with air forces around the world and saw action with the Israeli Air Force during the Suez Crisis. A less adventurous tasking involved duty as target tugs while others took to the seas as a carrier-borne variant sporting folding wings.
To the very end, the Mosquito continued to fill roles that no other aircraft could. The model continued onto the Mk. 43 which was a trainer with the RAAF, but there were so many variants and marques before the final propeller stopped.
I had the pleasure to be interviewing a ‘Battle of Britain’ veteran who in 1942 received a new posting to a Mosquito squadron with some trepidation. He had heard very little of the new type other than the fact it was wooden and therefore seemingly a backward step in fighter technology.
He went on to fly the Mosquito more than any other aircraft and commanded a Mosquito squadron post war. He never lost his affection for the ‘Mossie’ he grew to love and sixty years later still had a twinkle in his eye when remembering de Havilland’s “Wooden Wonder”.
Overhead Sydney's Kingsford Smith Airport.
As the numbers continue to soar on this blog and a new group of readers join us, I thought it would be worthwhile to re-visit five of the most popular aviation blogs thus far. Here they are.
1. Golden Days.
For those of you new to this aviation blog, welcome aboard! And for those that are continuing to come back, thanks for your support and please enjoy the growing list of original content.
We in the aviation world are actually a little further ahead of the game. We don’t give ourselves enough credit, but while corporate entities strive to maintain a level of secrecy, aviation seeks to share its shortcomings. The dissemination of safety findings on a global scale in an effort to circumvent repeat occurrences is one of our industries greatest achievements. When faults are found with aircraft, or the way in which we may operate them, that information is freely broadcast. It is a level of operational maturity that has not been achieved overnight, but it is a work in progress we can all be proud of.
Air safety investigation has come a long way over the decades. Rather than simply attributing every smoking wreck to “pilot error”, our knowledge based has broadened to delve deeper. We recognise that the finality of an accident is the result of numerous factors slipping through the net before ultimately combining in a lethal cocktail. The pilot is the final line of defence and sometimes he is just not enough. Sure, there are still instances of rogue pilots blatantly contravening every rule of good sense, but fortunately they are in the vast minority.
From ICAO and the national regulators of aviation down to individual operators, the pursuit of safety is an ever developing challenge. At its very core, success lies in open, honest reporting. Everyone has the ability to observe and speak up and in its most basic form; this is one of the places where safety begins. It may be wrapped grandly in a formal reporting system, or bound in the pages of an official accident report, but fundamentally it is about being honest. Whether it involves reporting potential safety issues or dissecting a tragedy in hindsight, there is no room for cover-ups or misplaced silence. Well chosen words may save lives.
But the road is not paved with gold just yet. There are still companies and cultures that do not encourage ‘speaking up’; whether on the flight deck or on a written form. In these environments, the benefits of safety have still yet to take full hold. Only when aviation professionals feel comfortable reporting mistakes and transmitting ideas can the group work together to minimise risks. Generally referred to as a “Just Culture”, it is an environment that encourages open communication without fear of reprisal.
So what does that mean to a lone pilot sitting in his Beechcraft Baron on a dark, wet threshold about to open the throttles?
It means that you are not alone. Somewhere before, a pilot has executed the same manoeuvre and contributed to the pool of knowledge that better prepares the next pilot. On such a dark wet night there are many dangers lurking. Sensory illusions due to acceleration trick the mind and only the instruments can be trusted. What if an engine should fail? Am I able to return to land or is there an escape path? Nearly every scenario that can be conjured has happened before and whether it culminated in a fatal crash or a moment of cold sweat, there is a lesson to be learned. The facts may be discovered by sifting through the wreckage or analysing a flight data recorder. Happily, they may also be found through self-reporting by a sensible, living, breathing pilot.
By whichever means the facts should surface, pilots should grab them with both hands. Aviation is an ongoing process of education and this is never more applicable than when we have the opportunity to read or the near misses and misfortunes of others. To the outsider this may appear ghoulish, but to those in the field it is cherished knowledge. Often sobering, these tales of misadventure fill the accident report sections of journals across the world.
It is equally important that we remain impartial as we digest the cold, hard facts. For in the safety of our armchairs it is impossible to recreate the mindset of another, or to feel the pressures and distractions that may have led to some terrible omission or oversight. It is not our place to judge with the benefit of hindsight, rather we should glean every ounce of knowledge that can be stored away for use on our own dark, wet night. Often, the pilot will have paid the ultimate price for a perfectly human error and there is nothing to be gained from slurring the reputation of another. In fact, such talk infers a sense of superiority and a belief that the mistake was merely simple and stupid. Beware! There is no room for such complacency in aviation.
I once watched a filmed re-enactment of the final approach of an ill-fated airliner. As the final stages of the approach became more hurried and communication more confused, error after error began to surface with increasing frequency. But rather than sitting in judgement, the hair rose on the back of my neck and a doomed sense of empathy with the crew stirred in my guts. I sat in air-conditioned comfort, knowing the final outcome of this approach, but I equally recognised the conditions that had placed this aircraft and all onboard in harm’s way. I could see the lurking demons of weather, systems failures, commercial pressure and fatigue stalking the hapless crew and I wanted to warn them from my comfortable chair. But it was all to no avail.
Far from sitting in judgement, I tried to take something from the tragic outcome that would improve my own operational performance. And so should we all when presented with safety information or the findings of an accident report. As with 'The Fatal Stall', from time to time this blog will re-visit a range of aircraft accident and incidents in an attempt to enhance the safeguards in our own flying. There will be no judgement placed on those who have ‘stared down the barrel’ in the accidents we review, rather we will endeavour to draw some positives from an otherwise unfortunate outcome. Nor will there be any sense of complacency, for there but for the grace of God, go I.
Chris Sperou doing what he does best.
The first full month at of this blog has come and gone.
When I launched the new website in December, I was venturing into the unknown. A little fish in a very big pond, I wasn't sure if anyone would actually find the website and blog. With so many commercial websites out there with online strategies and advertising, I accepted that I may just be a voice in the wilderness. You have all proven this to be very wrong.
Over the last few weeks the response to the blog has been exceptional. I have made over 50 posts since its inception, but already there have been more than 5,000 unique visitors and well over 10,000 page views! Equally significant has been the messages, comments and subscriptions to the website that have been flooding in. Very kind words and worthwhile feedback; please keep it coming!
For it is my desire to share this wonderful world of aviation that drives me to put in the effort, but it is your interest that will ultimately determine the future of the blog. The fact that so many people are reading the articles inspires me to keep going and I thank you all for that.
So, with the first full month behind me and the future ahead, I maintain committed to producing more original content on a broad spectrum of aviation topics. So please continue to come back and visit, follow me on Facebook and Twitter and let me know what you think. This has been a big first step, but I can't wait for the rest of the journey.
Thanks again for the huge support of my new aviation blog.
I encourage you to follow me on Facebook for the latest updates by simply clicking on the Facebook 'F' icon at the top of this page. That will lead you to my Facebook page titled "Owen Zupp. Author". Then simply click on the 'Like' button.
And for those already following the blog and Facebook page, please feel free to spread the word. Stay tuned for more new upcoming content.
As images of the Costa Concordia blinked across the globe, the sight of the huge cruise ship stranded upon the rocks was almost beyond comprehension. And yet, as controversy raged about the Captain's actions, one could not help but recall the day three years ago when a US Airways Airbus A320 ditched in the Hudson River. In this case the crew were applauded as the seemingly impossible had been achieved. Those images showed an intact airliner with itsprecious human cargo stood huddling on the wings. Even so, almost as quickly as the Airbus engines had spooled down, a single question surfaced, “How?”
There is no denying that New York is truly the city that never sleeps. From the town that burnt scenes of airliners plunging into the Twin Towers into our consciousness emerged vastly contrasting images of survival and hope. Amidst a flotilla of ferries, the Airbus bobbed gently in the frozen water as its passengers were evacuated to shore in an orderly manner.
US Airways Flight 1549 was not an isolated incident in history. Land-based aircraft have been forced to use water as an emergency runway almost as long as there has been powered flight. Whilst the instances of ditching airliners are relatively rare, a range of aircraft from Super Constellations to Convairs have ultimately ‘landed’ on water. In 2002, a Garuda B737-300 was forced to ditch near Java, whilst a chartered DC-3 put down in Botany Bay in 1994 after both engines failed after take off out of Sydney, Australia.
What made the Hudson River episode so intriguing was the relatively unscathed appearance of both man and machine as it became evident that the ditching had been made with minimal or no thrust. In such a time critical emergency, there are so many factors at play working against the crew. However, US Airways Flight 1549 proved that sometimes the planets can align.
Against the Odds.
The variables confronting a crew in any ditching situation are enormous. The available aircraft systems, the water’s swell, aircraft design, time of day and proximity to landfall are just a mere handful of considerations that must enter the mind of a pilot as the inevitable nightmare of ditching looms in the windscreen.
Achieving clarity amongst this background hash can prove a key achievement in itself and critical to a successful outcome. As in all emergency situations, the overwhelming priority must be to fly the aeroplane. Even so, there will be factors beyond the crew’s control with which they will have to deal on the day.
A variety of aircraft have ditched over the years and a number of those have been void of thrust. The reasons are varied from flameouts in ice and heavy rain, to the serial offender of fuel starvation. Whether a ditching is to take place with or without power affords the crew a very critical component; time. The powerless Airbus on the Hudson had no such luxury as inertia and gravity dictated its time frame once it had ingested the flock of geese.
Even when an aircraft’s remaining power may not be sufficient to maintain level flight it may provide enough to time for the crew to limp closer to landfall, sustain various aircraft systems, or control the rate of descent in the final stages prior to impact. Meanwhile in the passenger cabin, this time can afford the crew an opportunity to prepare the people and equipment for the ditching.
The availability of power will also determine the availability of aircraft systems from hydraulics to electrics. While most airliners have at 30 minutes of battery power to power minimal electrical systems, the resultant loss of hydraulic pressure may limit the amount of flaps and powered controls that are available to the pilot, depending on the particular system. A number of types, including the A320, are equipped with a Ram Air Turbine, or RAT, that extends into the airflow and spins over to provide and alternate source of power and pressure.
Ironically, some of those that have been forced to ditch without power have unwittingly exhausted their fuel supply whilst attending to a lesser in-flight emergency. Once again it gets back to the cardinal rule of aviation: Fly the aeroplane.
Aircraft design can also play a hand. Whether the wings are mounted high or low and if the engines are under slung on the wings, or aft mounted on the fuselage. All of these design features play a part, particularly in how the aircraft first contacts the water and decelerates. Once on the water, the low wing may assist egress, such as the images of passengers standing on the wing in the Hudson, or hamper it in such types as the Cessna singles where the door lies below the wing.
Whether the selected water mass is a river, lake or ocean can greatly influence the outcome of a ditching. While this can determine the proximity of the aircraft to landfall and rescue, it also can also dictate the water surface conditions. The prevailing swell is a major factor in the execution of a ditching and, generally speaking, the ocean is the home to the big swells. The American Great Lakes may have phenomenal seas, but generally a river or lake will present a more level surface for the aircraft to land on.
If an aircraft is forced to ditch at night, many of the visual clues may be lost unless a bright full moon can illuminate the white caps. Early assessment of the water surface and swell may be impossible and a ‘best guess’ plan must be devised on the planned prevailing winds at a lower level. Descending in the darkness will also make the actual approach and touchdown far more difficult to judge as there will be no runway lights in the peripheral vision and no horizon ahead to assist in assessing the rate of closure. Flight instruments and radio altimeters will be critical in guiding to the aircraft to the final moments and support calls from the ‘pilot not flying’ (PNF) will free the flying pilot to divert some attention out the windshield to catch the first glimpse of the waves in the landing lights.
Similarly, poor weather and a low cloud base will greatly reduce the visual information available to the pilot to execute the manoeuvre. Breaking out beneath the cloud base at low level with rain thrashing against the windscreen may leave the pilot with less than a minute of poor visibility to guide his aircraft to the surface.
The crew of US Airways Flight 1549 had daylight, reasonable weather and a relatively smooth water surface working in their favour. But -and it’s a BIG ‘but’- they had lost both engines and were effectively a 60 tonne glider. The crew had only minutes from losing the engines to touching down on the Hudson in which they had to decide, plan and execute their course of action.
A Landing with a Difference.
Landing on water is not the natural environment for aircraft not equipped with floats or a flying hull. Each manufacturer will make recommendations on how to best ditch their aircraft, though thankfully it is often not the voice of experience. The advice may stem from computer models, similar past ditching or pure hypothesis.
Generally speaking and where possible, the goal is a controlled touch down at the minimum safe speed, with the wings level, landing gear retracted and a minimal sink rate. Healthy conjecture will always flare amongst pilots as to the best means to achieve this. Thankfully, it will remain theoretical discussion for the great majority.
To achieve the lowest speed over the water, a landing into wind would normally be the prime choice. However, the swell also needs to be considered as landing head on to a rolling wave will exclude the chance of a smooth touchdown. Hence, landing parallel to the swell is advisable.
The selection of flap is also often debated. While the ditching procedure in certain manuals calls for the use of full flap to minimise the speed and afford better visibility at touchdown, these checklists are also predicated on having thrust available to control the rate of descent. (And enough time to carry out the checklist.) Often a mid flap setting is suggested to offer a compromise between reduced speed, sink rate and wing configuration on first contact with the water, particularly if the approach is without power.
The flare, hold off and touchdown is critical. Judging the flare over water is void of the normal cues associated with landing and can prove difficult, particularly over calm, glassy water. Similarly, not too many pilots are routinely judging the landing flare with their wheels retracted and the associated changes in height and ground effect. Keeping the undercarriage retracted is designed to prevent the wheels ‘digging in’ on touchdown and pitching the aircraft violently into the water.
Maintaining a wings level attitude will also guard against one wing striking the surface first and slewing the aircraft around in an uncontrolled manner. This was graphically illustrated in the case of the widely circulated footage of the Ethiopian Airlines 767 of Comoro in 1996.
Approaching touchdown, at around 500 feet, the flight crew will warn the cabin to brace for impact. Dependant on the aircraft type, the ideal nose attitude is cited to be in the realm of 10-12 degrees as the water looms close and contact with the surface is imminent.
A smooth, single touchdown on the aft fuselage is the goal, though often not the case. ‘Skipping’ along the surface will inherently expose the aircraft to a series of impacts, but in reality, touching down in a relatively ‘clean’ configuration there is a high chance of more than one contact.
In the end, on the day there will be compromises and judgement calls based on the remaining aircraft systems, time available and prevailing conditions. If it all comes together successfully, there will be some very grateful passengers and the possibility of a slot on the talk show circuit.....
Check back soon for part two of 'Sink or Swim'.
Title Image. KLEWTV.COM