Being Prepared.

As with all emergencies, sound training before the event is vital. In the case of ditching, the training provided varies widely between operators. Often the degree of overwater operations will be a determining factor in the level of training provided. Whilst ditching training may be a core component of emergency training to off-shore helicopter operators, the same may not be true for those flying inland scenic flights.

It will always be impossible to train for absolutely every contingency in every emergency situation. Whilst budgets and time constraints may play a part, the varying scenarios of each emergency offer much too broad a spectrum to cover. Not to mention those events that our imaginations are still yet to conjure. As such, all emergency training is designed around regulatory requirements, training budgets and probability.

Airline training departments and aviation authorities design their syllabus to a background of risk management to assure that as wide a spectrum of non-normal situations as possible is covered. In turn, beyond the initial training, a recurrent program will provide ongoing training for the entire career of both flight and cabin crew.

The focus of training is linked to a factor of likelihood and by all accounts ditching falls into the ‘remote’ category for multi-engine jet transport operations. This is not purely a function aircraft engines’ ever-improving reliability or their safety in numbers. The regulations for over water operations are stringent and seek to ensure that the aircraft can at all times divert to an alternative airfield in the event of a critical systems failure.

Even so, it is a case of double jeopardy to lose ALL available engines and be forced to land on the water. The Hudson River case also proves that the aircraft doesn’t need to be over the middle of the Pacific Ocean to end up floating.

To this end, ditching training at airlines falls into a category of its own. The process of ditching is discussed at length in the manuals and crew training in emergency equipment, life rafts, evacuations and subsequent survival is ‘hands on’. Crews are scrutinised on these skills annually by both theoretical and practical examination. A failure to meet the regulatory body’s set standards results in the crew member receiving further training before they are allowed to return to line flying.

Yet in this stringent training environment, the training of pilots to fly the actual ditching manoeuvre in the simulator is not a mandated exercise by the FAA (US), UK CAA or CASA. That is not to say that individual operators do not include it in their syllabus of training, or that flight crews have not taken it upon themselves to rehearse for the eventuality during simulator training sessions. Simply, to date it has not been regulated. This may well stem from the risk assessment of the probability of ditching when compared to the incidence of other emergencies such as engine failure or depressurisation.

In a similar way, the thought of losing all four engines and their associated systems on a Boeing 747 was previously thought to be virtually impossible. Then in 1982, British Airways Flight 9 encountered volcanic ash over Indonesia with the subsequent loss of thrust on all engines. Again, the crew performed admirably in a situation beyond the scope of their training and manuals to ‘adapt, improvise and overcome’. Subsequently, the books were re-written, simulator training was updated and checklists modified. Today, pilot education of volcanic ash and its effects is routine.

This may well prove the case with ditching as well. Simulator exercises ‘reverse engineer’ the data from such incidents and use the lessons learnt to train pilots. With the data generated from US Airways Flight 1549, it is quite possible that a change in the training requirements in this area will be forthcoming.

Getting Out.

So many factors came in to play in the case of the Hudson River ditching, not the least of these being an experienced and well trained crew on both sides of the flight deck door. The two pilots had over 35,000 hours experience between them, while the three flight attendants had a total cumulative service in excess of 80 years!

For a successful outcome, the entire crew had to perform their designated roles to the best of their ability and, seemingly in this instance, at a level above. This was critical, not just in executing a successful ditching, but in safely evacuating 150 passengers.

Evacuations are generally described as prepared or unprepared, depending on whether the crew has had enough time to ready the cabin, its contents and passengers for the evacuation. It is also an opportunity to call for the donning of life jackets. The flight attendants would have had some advanced warning on Flight 1549, but it would have been minimal. Fortunately, as the aircraft had just lifted off, the catering carts and crew may well have still been secured away.

On coming to rest, the cabin crew is now faced with assessing the available exits, launching the rafts or slide rafts and evacuating the passengers with a minimum of time and panic. It is a fine balance to maintain order in the cabin while they undertake their duties and voicing loud, concise commands are central to organising the potential chaos. These are the very scenarios and drills that cabin crew train for year after year throughout their career.

A water landing presents the additional challenge of available exits. Notwithstanding fire, damage and extreme aircraft attitudes, in a land evacuation most exits are generally available. This is not necessarily the case when the aircraft is afloat. The attitude with which an aircraft settles on the water may preclude the use of certain exits, particularly the rear doors if the aircraft sits tail low and the door sill lies below the water line.

To further aid in keeping the hull watertight, the A320 also has a “Ditching Pushbutton” on the overhead panel. When activated, the guarded switch automatically closes valves and inlet doors which will lie below the water line.

The A320 is certified so that all doors and overwing exits can be used in a ditching and accordingly are equipped with escape slides. Despite this certification, it is a primary task of the crew that the viability of the exit is assessed before opening the door, as a door below the water line will allow the water to come flooding in and further impede the stricken aircraft struggling for buoyancy. Preventing over-zealous passengers from cracking these doors open in haste is yet another duty for the crew.

Opening the door will result in differing scenarios based on the aircraft type. For some aircraft, the escape slides double as life rafts, while others call for the crew to manually launch rafts that are stowed elsewhere in the cabin. Similarly, distress beacons can be integral to the rafts, or launched independently.  The evacuation is only started at an exit when these rafts are inflated and ready to accept passengers. It is also imperative that the life jackets are only inflated when clear of the aircraft. Another tragedy associated with the Ethiopian Airlines 767 ditching was the death of passengers within the aircraft having survived the impact. With their jackets already inflated, they floated to the aircraft ceiling and were unable to escape via an exit.

With doors open and the slides or rafts inflated, the passengers are shepherded towards the exits in a speedy manner to clear the aircraft before it can submerge. The crew will check the cabin again to ensure that all of the passengers have evacuated before being the last to exit. Once clear, survival and rescue become the next priorities. Again, the crew have been trained for contingencies varying from desert survival and dehydration to arctic hypothermia. The crew of Flight 1549 fortunately ditched close to land with a readily available flotilla to ferry the passengers to safety. Facing any significant time in the sub-zero waters may well have resulted in a different outcome.

It is said that cabin crew are there to provide the passengers with life saving assistance in an emergency. When the emergencies are not taking place, they are available to provide cabin service. This is not only a truism, but a very healthy mindset for all those involved with air transport. The crew of Flight 1549 and their wealth of experience emphasised the critical role to be played by those in the cabin in case of emergency.

In the Wake.

Being confronted with a multiple engine failure is the dread of any flight crew. To be further confronted with ditching the aircraft with only minutes to react is the stuff of worst case scenarios.

Yet events such as US Airways 1549 and the British Airways 747 left powerless by volcanic ash have proven that ‘worst case’ can on occasions become reality. The investigators will seek out the facts, volumes will be written and procedures modified. As proactive as aviation safety endeavours to be, sometimes  lessons have to be learnt from experience. Undoubtedly this will be the case again in the wake of the Hudson River ditching.

Fortunately, landing a jet transport aircraft on water is a rare event. Despite the mass of variables that can confront a crew and the time constraints that may be imposed by fate, training, experience and measured, appropriate responses can make the seemingly impossible survivable. It is a credit to the entire US Airways crew that all of the passengers went home to their families.

Safety briefing cards in the seat pockets and preflight presentations are provided with the hope that the actions contained therein are never required. In the same way flight and cabin crew train for most conceivable eventualities year after year, crossing their fingers that simulations are as close as they get. Yet time and again when the unthinkable has occurred, training has kicked in and the crew prove that they are up to the task.

The ability for a crew to ably fulfill their roles when confronted with an emergency is a function of both thorough training and the correct mindset under pressure. The landing of US Airways Flight 1549 on the Hudson River is testimony to this. These are invisible intangibles to the passengers as they board yet another routine flight, yet are possibly the most valuable component of the ticket price.

Should the unthinkable occur and their aircraft is faced with ditching, it will be this training, preparation and mindset that dictates whether they sink or swim.

Title Image. edp24.co.uk

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