Question for Clanad

[sddsddean]

Being our US airline guru, hope you can answer this. Yesterday, before flying home, I was watching the aircraft taking off from EWR (Newark Int) on runway 22. They all got up to around 500 feet and turned left. Now while a few carried on eastwards, the vast majority after doing this left turn shimy almost immediately turned right (at around 900 feet), presumably to head into the 'US'. My question is do you know why they do the 'left right shimy'? My first thought was that they were trying not to overfly something, but looking on Google Earth I can't see anything odd. The answer is of no use as such...just to satisfy my curosity!!

[Clanad]

Good question and I'd have to say you're very observant... Having flown in and out EWR numerous times, I'm very familiar with the departure procedure you describe... Here's an excerpt fro an air traffic contorller a number of years ago to The House of Representatives committee on infrastructure on air traffic departures at Newark (November 4, 1999) :
'Newark International Airport has three runways: one east-west runway (11-29) and two parallel north-south runways, 22 left and right ("22 L/R"). Staten Island is south of the airport and there are communities, such as the City of Elizabeth, which are southwest. Since 1952, aircraft departing runway 22 have turned south to avoid over-flying the city of Elizabeth. Since 1961, departures from Newark off runway 22 L/R have climbed to approximately 500 feet, at which point the aircraft make a left turn, heading 190 degrees. This departure route avoids over-flying the densely populated areas of Elizabeth. This route passes over an industrial area located between the City of Elizabeth and a waterway, known as the Arthur Kill, and then over the northwest corner of Staten Island. As air traffic operations at Newark have increased, residents of New York and New Jersey have been requesting a change to air traffic procedures to reduce noise in their communities."

The Commitee did not and has not changed the procedure. Additionally, you may not have noticed a significant power reduction at about 500 feet as well. This does reduce noise somewhat, but has alwys been highly controversial at EWR and other airports where it's imposed...

[sddsddean]

Thanks very much...curosity satisfied!!

[filthiestfis]

Brilliant question and answer from Clanad. Sorry to step in but im curious as to why the power reduction at 500 feet is considered to be controversial. Perhaps you could elaborate on that?

[Clanad]

Sure... the most dangerous part of any flight, as far as I'm concerned, is the part of the climb profile that occurs just after lift off. The aircraft has reached the speed at which it will climb on one engine very nicely. However the ensuing climb with both engines working is done at V2... a speed only several knots above the stall speed of the aircraft. It happens to be the most efficient climb speed so as to reach altitude as soon as possible, which provides the extra saftey factor in case an engine fails. The goal is to climb to 800 feet above the surface at this speed and then lower the nose of the aircraft incrementley to beign accelerating as well as still climbing. To reduce power in the middle of this critical part of the profile simply interjects another risk factor and, in my opinon, does little to reduce the noise level on the ground. Especially in todays highly efficient, high by-pass ratio turbo-jet engines.
There was a time a jet engine sounded like... well... a real engine. Lots of smoke, lots of noise. (In fact a standing "inside" joke was that the sole purpose of a jet engine was to turn keorsene into noise). New generation engines are quieter and much more fuel efficient...