Quote:
Originally Posted by neel385 Most of the modern generation fighters are Fly by Wire which further makes the job of handling asymmetric thrust easier.
In a fighter with both the engines close to the centerline, I do not really see the requirement, though in older multiengine fighters, pilots had to manage throttles separately, specially when the thrust of both the engines were not the same resulting in yaw. In modern fighters, the thrust of both are matched by the Engine Computer(ECU). In certain Thrust Vectored Aircraft, the ECU is known to adjust the thrust from both the engines separately in consonance with the pilots manoeuvre demands.
In the case one engine malfunctions, the ECU will take over and try to recover the engine, failing which the engine will be shut down with associated warnings to the pilot. Does it really matter if the pilot does the job manually as with two throttles or the ECU does the work for him? |
I don't think fly by wire makes handling asymmetrical thrust easier perse. Compare the engine our procedure for an Airbus 320 (fly by wire) against a Boeing 767 (non fly by wire) and you will find they are near identical.
Engine out scenario's are first and foremost recovered by flight controls, i.e. rudder, ailerons and possibly elevators. And subsequently dialed out by trim adjustments. Any 1980's auto pilot (i.e. Honeywell series) has already been able to do so. At least on GA planes and commercial airliners.
When you fly manually, you go through the same motion, fly by wire or not. In such a scenario, ie engine out, hand flying, and with fly by wire, you could envisage that the computers once they detect an engine malfunction occurs, start dialing in rudder, elevator, aileron to trim out any yaw. But I would think that it is counter intuitive for a pilot flying manual. This could lead to the pilot overcompensating,and could lead to Dutch roll or worse.
So it's more about the design philosophy than what is technically feasible.
I fly with autopilots and I'm fully aware on how the autopilot trims my plane when I engage it. But when I fly manually I don't want any computer overriding my control inputs.
My question was more about in planes such as the Rafale that have only one thrust lever for two engines how do you control engines separately in emergency scenario's? As I said, I'm probably slightly biased as I have only experience in GA aircraft. And I have a surprising amount of hours on the 747-400 Full Motion crew training Simulators of Lufthansa and Cargolux.
On aircrafts losing an engine it is not only about losing the associated thrust. You also lose the electrical, hydraulical and pneumatic power provided by that engine. On a twin engine jet these systems will be fully redundant, and I assume in fighters one engine will provide sufficient electrical, hydraulic and pneumatic power to fly the plane more or less normally.
There are many engine problem scenario's where running the engine at reduced power settings or even at idle, are preferred to shutting down all together. Purely for safety measure. What I got drilled into me by Lufthansa flight school is:
- First of all, deal with the emergency and stabilize the situation
- Two, plan ahead on what would happen if the next failure occurs.
So keeping one engine running even on idle is a good preventive measure in case something happens to engine number two and you might have to shut it down all together. To a large extent you can program this. But under these circumstances, it comes down to pilot discretion and decision. Maybe run an engine into the ground, but maintain standby electrical and hydraulic power. And for that you need manual control of the engine, manual monitoring of the engine parameters. So how do you do that in the Rafale, or is it all programmed into the flight management computers?
Jeroen