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Overspeed

NShadow Guest

How do I avoid this problem? I try to achieve the cruising speed with autopilot but I always get an overspeed warning.

For examplary purposes , aboeing 734's cruising speed is mach 0.78 but I cant reach that figure. And its clear weather. So i dont think theres headwind.

whats wrong? is it that the indicated airspeed is different at different altitudes?

8 Responses

Pro Member First Officer
to_coolguys First Officer

Do you turn the Autothrottle on??There are a lot of factors majorly of them being the Flight Level of your cruise, weight of the airplane..
Because if you are weighing too heavy,then you will not be able to reach the desired cruise altitude..What i would suggest you to do is a step climb ..Step climb is reaching a intermediate altitude and staying there for some time to burn fuel and reduce weight.Then climb to another intermediate altitude and staying there for some time unless you become light..Then start climbing to your cruise altitude..Here the Vertical speed is also an important factor..You can climb at a steep vertical speed rate as you move on at higher altitudes..

NShadow Guest

yeah autothrottle is on. i autopilot a lot these days. so you mean when the aircraft weighs less and altitude is appropriate (30,000ft for a b734 i believe), maximum allowable airspeed is increased?

do real planes load their planes 100% fuel before every flight?

also a little offtopic but do all real pilots land with ILS all the time?

Pro Member First Officer
to_coolguys First Officer

well to be honest..Disregard my prev post..I was thinking of cruise altitude and not cruise speed...

Pro Member Chief Captain
CRJCapt Chief Captain

Aircraft are subject to two types of airspeed restrictions set by the manufacture for safety reasons, these limits vary with altitude. The first limit is at lower altitude and is called Vmo-Maximum operating speed. This is a limit in KIAS that's normally around 320-360 KIAS and effective up to Flight Level(FL) 280-290(28,000-29,000 ft.). Above this altitude, the limiting speed is Mmo-Max. operating speed(Mach) and is expressed in percent of the speed of sound(the speed of sound is dependent on temperature) or Mach. This is normally around Mach .82-.88 depending on the aircraft. These speeds are listed in the aircraft documentation in FS.

The temperature, as an aircraft climbs, normally decreases. Mach .78 is faster at FL200 than at FL 350 because of the temperature difference. Normally aircraft have to be above FL 280 to achieve stated cruise Mach values.

Fuel- Large aircraft almost never take off with full fuel. Fuel load is based on the distance of the flight, 45 min reserve and any other fuel required to reach an alternate airport(if required). Full fuel would restrict the number of passengers and bags. Sometimes aircraft have to restrict the fuel load on a short flight because they will arrive at the destination with too much fuel(above Maximum Landing Weight).

ILS-The ILS is the normal aid for a large aircraft at a large airport in poor weather. During good weather, if available, pilots back up a visual approach with the ILS or other approach aids. Some runways are not equipped with an ILS and pilots are fully capable of landing a 747 on a runway using nothing more than their eyes.

I hope this in formation helps. 🙂



Last edited by CRJCapt on Fri Feb 02, 2007 12:31 pm, edited 2 times in total
NShadow Guest

very helpful. i get it now. very understandable. now my FS experience is that much better. 😀

Pro Member Chief Captain
CRJCapt Chief Captain

👍

Pro Member First Officer
pilatflyr First Officer

i second that

Pro Member First Officer
to_coolguys First Officer

very informative...CRJ...ANother piece of aviation knowledge in my armour... 👏

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