DAVID CONNOLLY,
Sir, - Kevin Myers makes some strident promulgations (June 19th) which I shall attempt to correct before Brendan McWilliams does so.
I quote: "It's all rubbish. A plane coming down over water loses the powerful lift generated by a thing called 'ground-effect'." Even in the event of a "considerate" technical problem that enables a pilot to glide over land, over the sea an aircraft will "drop so fast that it will smash to pieces on impact".
"Ground-effect" is a reduction in "lift-producing drag", known as induced drag near the ground or water when the aircraft is one wingspan's height above the surface, as the surface acts as a barrier to the induced drag vortex. On June 24th, 1982 a British Airways 747 en route from Kuala Lumpur to Perth lost all four engines over sea due to volcanic ash end and glided for nearly half-an-hour before starting three engines out of four in clear air and landing safely in Jakarta. Not exactly an uncontrolled fall.
Mr Myers goes on to say in his "Laws of aerodynamics" section about a water landing/ditching: "Do you understand? This has never happened . It can never happen. The laws of aerodynamics will ensure it never happens." On May 2nd 1970, a DC-9 of Overseas National Airways, leased by ALM, en route from New York JFK to St Maerten in the Dutch Antilles, ran out of fuel and ditched in stormy seas. Forty out of 63 souls on board survived.
The plane floated for only 10 minutes as its hull was breached upon impact with the water.
Regarding hijackers, as has been well illustrated last September, if they can't be stopped on the ground, one's aerial options are limited. I agree with his points on tweezers and bottles, however.
Never is a dangerous word and a little knowledge is a dangerous thing. - Yours, etc.,
DAVID CONNOLLY, Aviation Consultant, Brussels, Belgium.