CASA has released a Civil Aviation Advisory Publication offering pilots advice on how to best prepare for and handle ditching events.
CAAP 253-1(1) was written as a result of Australian Transport Safety Bureau (ATSB) Safety Recommendation 2000258, which recommended that CASA educate the industry on the procedures and techniques that may maximise the chances of survival in a ditching event.
While the majority of aircraft aren’t designed for ditching, research estimates that 88 per cent of controlled ditchings in the US and UK result in few injuries to pilots or passengers.
An aircraft’s design significantly influences how it will behave upon ditching impact – generally speaking, aircraft with an almost straight fuselage under surface will behave in a more benign manner than those with a swept up rear fuselage.
CASA warns one of the most difficult things to get right in a ditching is judging the height for the flare and hold-off, and notes that one light aircraft manufacturer recommends their aircraft not be flared at all in a ditching due to the difficulty in judging the height above the water surface and the potentially serious consequences of a stall. And the difficulties in judging height over water are exacerbated when the water is calm, or when ditching on a very dark night.
Aircraft flight manuals generally include detailed handling information for the execution of a ditching, but as part of the CAAP 253-1(1) CASA has issued the following 10 points for pilots to consider should they find themselves in the unfortunate situation of having to ditch:
- Don a life jacket if time permits.
- Reduce the aircraft’s weight to a minimum if you have time and if practicable to reduce stalling speed and therefore your planned impact speed.
- Ensure landing gear is up (if applicable) and the associated circuit breaker is pulled.
- Dispose of, or restrain, any loose articles in the cabin that could create a hazard during impact.
- Consider possible airframe distortion on impact and arrange to have an escape door or hatch open before impact so you can vacate the aircraft.
- Make every effort to precisely control airspeed and rate of descent – both should be as low as possible, consistent with maintaining full control of the aircraft. If conducting a glide approach consider approaching at a higher speed, which will provide the lift energy necessary for the larger than usual flare required to achieve an appropriate rate of descent at impact.
- Ditch into wind if possible, otherwise ditch along the swell. A compromise may be necessary in extreme cases.
- Use flaps set to a medium position to ensure the slowest speed on impact. Flaps also usually induce a lower angle of incidence and therefore smaller aircraft body angle when approaching stalling speed, thus providing for a better aircraft attitude on impact.
- If possible make the approach using power. If the ditching has to occur because of impending fuel exhaustion, make the approach before all the fuel is expended. A powered approach provides for the greatest potential to execute a successful flare and hold off, enabling the aircraft to have almost no descent rate at impact.
- Be prepared for a violent impact. There will probably be two or more impacts – the tail end of the aeroplane followed by the entire fuselage.
CASA advises pilots to review their plans for ditching and subsequent survival before long flights over water and to adhere to a checklist that should include the following:
- Plan to ditch using power if you have a choice.
- Look for likely rescue sources (ships, shorelines).
- Make Mayday calls (see ERSA for the correct format) and set transponder code to 7700.
- Study the wind and sea surface then make a plan of action for the direction of the ditching manoeuvre.
- Burn off or jettison fuel if possible to ensure the aircraft is as light as practicable.
- Jettison any freight and other unnecessary heavy objects.
- Brief all crew and passengers, covering their actions and responsibilities before and after the ditching including the use of a life jacket.
- Ensure all survival equipment is readily accessible, including your personal locator beacon.
- Make a final decision on the direction of ditching.
- Set up the final approach not below 500 ft above the surface.
- Unless the aircraft manufacturer recommends to the contrary, if you can accurately judge the height of the aircraft above the water, round out at the usual flare height and hold off until impact, ensure rate of descent is less than 200ft per minute and wings parallel with the water surface (level for a calm surface).
- After the aircraft stops, vacate, taking all necessary gear.
- Only inflate your life jacket when outside the aircraft.
CASA stresses that, as well as these general points, your ditching checklist should be tailored to your mission and aircraft type. For further information contact CASA’s Operational and Flight Crew Licensing Standards Branch by phoning 131 757.
(John Absolon)
