Does A Loss In Airspeed = A Loss In Altitude?

[lenbrazil]

I am debating someone in another forum about the Wellstone crash. Neither of us are pilots. He made the following statement which doesn't make sense to me.

"the NTSB said they lost track of their airspeed, that cannot occur without a commensurate loss in altitude"

This doesn't make sense to me so if they speed up they automatically gain altitude?

Len

 

[PRINCESS KIDAGAKASH]

If you are flying along straight and level and make no changes to the trim,angle of attack of the airplane and reduce power,the airplane will start to lose airspeed and altitude. If you add power your airspeed and altitude will start to increase. To maintain altitude after reducing power you would have to trim the airplane with more nose up trim,pull back on the elevator, or if getting into a landing pattern lower your flaps to provide more lift to prevent a stall. It's kinda difficult to explain all the factors at work here without some pictures to demonstrate certain things. A lot of this stuff you don't even really think about while piloting an airplane. It just becomes second nature. I will tell you one thing though a good pilot always keeps an eye on the airspeed indicator while taking off or landing. After reading the NTSB report on this crash it looks like the pilot's just didn't keep an eye on their airspeed as they were coming in to land.

 

[lenbrazil]

If you are flying along straight and level and make no changes to the trim,angle of attack of the airplane and reduce power,the airplane will start to lose airspeed and altitude. If you add power your airspeed and altitude will start to increase. To maintain altitude after reducing power you would have to trim the airplane with more nose up trim,pull back on the elevator, or if getting into a landing pattern lower your flaps to provide more lift to prevent a stall. It's kinda difficult to explain all the factors at work here without some pictures to demonstrate certain things. A lot of this stuff you don't even really think about while piloting an airplane. It just becomes second nature. I will tell you one thing though a good pilot always keeps an eye on the airspeed indicator while taking off or landing. After reading the NTSB report on this crash it looks like the pilot's just didn't keep an eye on their airspeed as they were coming in to land.

[post="305948"][/post]​

OK so let's imagine you have a poor distracted pilot. If he inadvertently lets the speed drop and doesn't adjust the trim or angle of attack etc. would a loss of altitude automatically ensue? Would the drop in altitude be "commensurate" with the drop in speed or might a sharp reduction in speed lead to only a small reduction in altitude?

Len

 

[delldude]

OK so let's imagine you have a poor distracted pilot. If he inadvertently lets the speed drop and doesn't adjust the trim or angle of attack etc. would a loss of altitude automatically ensue? Would the drop in altitude be "commensurate" with the drop in speed or might a sharp reduction in speed lead to only a small reduction in altitude?

Len

[post="305983"][/post]​

OK so let's imagine you have a poor distracted pilot.

kennedy ring a bell?
loss of speed = loss of lift = loss of lift gravity takes over.
loss of altitude converted into an increase in speed at a downward angle.especially if not paying attention....
pull up...pull up...

 

[goingboeing]

"Thou shall watch thou airspeed or the earth shall rise up and smite thee."

This was taught to me by a pilot who was a member of the Hump Back Pilots Association.[Burma-India-China- WW2]

If you have ever been to an airshow listen to the announcer use the phrase
"He/She is trading altitude for airspeed".The wing will not fly indefinitely without airflow[airspeed].Other factors are also important such as angle of attack.One could stall a wing in a vertical high speed dive.

Airspeed is one of several critical factors that keep a wing flying.

 

[www.SquawkAviation.com]

I am debating someone in another forum about the Wellstone crash. Neither of us are pilots. He made the following statement which doesn't make sense to me.

"the NTSB said they lost track of their airspeed, that cannot occur without a commensurate loss in altitude"

This doesn't make sense to me so if they speed up they automatically gain altitude?

Len

A reduction in airspeed doesn't mean a loss of altitude is going to follow. If you conserve the energy forces acting on the plane, you can maintain altitude. However, increasing airspeed can cause an increase in altitude, theoretically, based on the physics of the wing structure. Planes are usually trimmed to prevent this from happening when in flight.

 

[SquawkAviation]

A reduction in airspeed doesn't mean a loss of altitude is going to follow. If you conserve the energy forces acting on the plane, you can maintain altitude. However, increasing airspeed can cause an increase in altitude, theoretically, based on the physics of the wing structure. Planes are usually trimmed to prevent this from happening when in flight.

This is particularly true for prop planes, such as the cessena 172

 

[lenbrazil]

Ok let's assume the airspeed loss is due to inattention on the pilot's part and he made no adjustments to trim etc. Could he plane maintain altitude or would inveriably begin to desend? Would the loss in altitude be proportional to the loss in speed?

The plane involved is a King Air A 100 if that makes a difference

 

[cybercat]

Planes are usually trimmed...


Will you please explain to a layperson what it means to "trim" a plane? :huh:

Thanks

CC

 

[SquawkAviation]

lenbrazil- If a plane loses airspeed without the pilot noticing while it's in trimmed flight, intially it will fly level but eventually it will start to lose altitude for two reasons. First, after some time has elapsed, friction will slow the plane down and if you try to maintain altitude at slower speeds, you will descend. Second, because the plane is trimmed for level flight at that specific airspeed, a decrease in airspeed will cause the plane to nose down. An unnoticed decrease in airspeed will cause the plane to lose altitude, especially if it's trimmed for cruising at that speed. I don't think that the loss in altitude will be directly proportional to loss in speed, but they are certainly related.

cybercat- Trim is something pilots use to facilitate level flight. The physics of the wing is designed to create natural lift, this is how flight is possible. At higher speeds, the force if lift is greater, creating a natural upward force on the plane. Planes have a mechanism called a trim wheel, which controls a panel on the elevator located in the rear of the aircraft. At higher speeds, pilots 'trim the plane down' meaning the panel on the elevator is raised so that their is now a downward force on the plane as well. This force cancels out the effect of the lift from the wings and level flight is made simple. Without the trim wheel, pilots would have constantly pitch the nose of the plane downwards to counteract lift forces of the wing.

 

[falk]

If the autopilot was set to hold altitude, a loss of airspeed wouldn't result in a loss of altitude until the plane stalled completely, or at least required more nose-up force than the autopilot could deliver. I believe there was once an airliner that nearly crashed into the ocean that way (crew pulled out of the dive at something like 4000' altitude)

Trivia: If you reduce throttle on a high-wing plane and don't touch the trim, the airplane will gain airspeed. I have confirmed this myself in a 172. Who here knows why?

 

[goingboeing]

If the autopilot was set to hold altitude, a loss of airspeed wouldn't result in a loss of altitude until the plane stalled completely, or at least required more nose-up force than the autopilot could deliver. I believe there was once an airliner that nearly crashed into the ocean that way (crew pulled out of the dive at something like 4000' altitude)

Trivia: If you reduce throttle on a high-wing plane and don't touch the trim, the airplane will gain airspeed. I have confirmed this myself in a 172. Who here knows why?

The old timer who was a member of the hump back pilots association taught me to think differently on APPROACH to the runway.He said to think that the contol wheel[stick]fwd and aft movement controls airspeed and the throttle controls altitude.

In cruise flight it is normal to think that the stick controls altitude and the throttle controls airspeed.