THIS ISN’T ABOUT POTUS.
Going through TV footage of Obama arriving and departing from JKIA on Sunday, I noticed something interesting which requires some explanation. When the two Ospreys and Marine one helicopter arrived at JKIA, they flew and landed near Airforce one as helicopters normally do. But on leaving (for those familiar with the airport), they taxied along the winding tracks on the airside to the runway and took off like normal aircraft. Why was this and why didn’t they just take off the same way they landed?
AM not an expert in aviation, but I think airports have a protocol on how and when to land and take off. If the ospreys needed a take off run to get into the air, they wouldn’t have gone to KU. Am sure they didnt make a run across the lawn there.
Helicopters have a designated spot marked with a letter H where they land but depending on traffic and on the discretion of the air traffic controller and depending on the undercarriage of the heli concerned,he/she can clear a heli to land on the runway,direct to a helipad or on the main apron. When giving clearances to land at anywhere else apart from the runway,the controller will give the wind speed and direction and inform him…land at own discretion. On taking heli that has rotatable undercarriage may request to taxi to the threshhold of the runway,in HKJK its Runway 06 for roll and take off. Those heli needed the ground run not vertical climb from the apron.
Due to the ETD of Potus and availability of space next to Airforce 28000(becomes AF1 moment potus enters) to save time and for security reasons it was only logical to clear the heli direct and park at own discretion and maintain own separation. On departure,the heli requested engine start and taxi in sequence to the runway. They would have lifted off from the apron if they requested to.
Drawing from basic principles, vertical takeoff should consume more fuel compared to runway takeoff.
@bjurmann ,I guess that is quite possible and logical. @Bus, I guess that taxi run from the apron to the runway is more than 3 kilometres and would consume more fuel than a vertical take off.
What language are you guys speaking.
Tafasari translate into a layman’s language
taxi run is more convenient imho
common guys, mnaniangusha, hadi wewe @Bus?
The reason why they taxied is because they were carrying a heavy load…A helicopter can only take off vertically with a certain amount of weight on them, which if exceeded, cannot take off. For this reason, for extremely heavy loads they are usually hung below the helicopter with some kind of cords (for lack of a better word) so as to allow the helicopter take off from the ground first and gain proper lift.
For the Osprey, they overcome this by taxing like a normal aeroplane so as to achieve proper lift…gerrit?
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Pia wewe umetudanganya. An aircraft has maximum take off weight that is never exceeded. Sio ati probox unaweka vitu tu vyenye unataka. Secondly a helicopter doesnt gain lift from speed or height. Lift depends on the speed of the blades, their size and their angle. For the hybrid aircraft it might be true that they had to make a run for take off when laden. The reason a helicopter carries a load hanging from outside is because the load is too large or logistics of loading aren’t convenient. The load doesnt get lighter when outside.
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mathiche is kungu the pilot
You can reason that way for the Ospreys, buy Marine One, which is an ordinary helicopter was there taxiing to the runway, leading the Ospreys. That can’t entirely be the reason.
Am not, my career is nowhere near aviation, real or imagined.
It’s done for several reasons
The down wash from the rotors combined with debris (foreign object damage)on the runway/apron can cause serious damage to surrounding vehicles and matter
For others is insufficient power to take off vertically when fully loaded like the mi-24 hind which has stub wings to aid with lift on a rolling take off. Also moving towards headwinds help a lot for heavy helos such as chinooks which can taxi with the forward wheels off the ground
Taking of vertically increases the strain on the rotors and engines. Whichever way is available to reduce wear and tear will be utilised
Zero airspeed take off leaves very few options in case of emergency. Coming straight down is more dangerous than gliding and survival rates are much reduced