Last you guys heard from me I’d just finished sim session number 2 and was feeling pretty good about it all. At that stage we’d covered mainly normal procedures such as take-offs, landings, and general aircraft handling. We’d also had a look at some basic failures.
Sim sessions 3 and 4 were rumoured to be the most challenging. I was soon to find out that the sessions would get very challenging until after session 5, by which time we’d both pretty much come to grips with flying the aircraft and handling the failures that were thrown at us.
Session 3 was where we were introduced to engine failures at V1/Vr.
V1 is the decision speed during the take-off roll. At any time before V1 you will have enough runway to stop in case there is a problem. After V1 you are commited to taking off. Vr is the “rotate” speed, the speed at which you pitch the nose up and take-off. In the Dash 8 V1 and Vr occur at the same speed, so at the time that you are rotating, you have also just committed to continue regardless of whatever failures may occur at that time.
This is the most critical time to have an engine failure. You are very close to the ground, you still have landing gear and flap extended, you have low airspeed, and you probably have obstacles ahead–such as rising terrain–that you may not be able to clear with the reduced performance that an engine failure gives.
The aircraft is also quite difficult to control when the engine initially fails, there is a significant yawing movement towards the failed engine and unless you act promptly to maintain control, it is easy to have large excursions off heading. Airspeed control at this time is critical. The speed that will give you the best angle of climb is known as V2 and all the climb performance guarantees given by the manufacturer are null and void if you don’t maintain the correct V2 speed when operating on one engine.
In order for the aircraft to perform adequately after take-off it is necessary for the propeller on the failed engine to be “feathered” this refers to the prop blades rotating so that their leading edges face directly into the airflow, minimising drag and preventing the props from windmilling. If the prop wasn’t feathered and kept spinning it creates a lot of drag, enough to cause the aircraft to lose altitude in a turn and possibly crash.
To ensure that the prop does feather, the aircraft has an “auto-feather” system. A little electronic box on the failed engine sends a signal to the operating engine and tells it to increase power by 10% (“up-trim”), it also sends a signal to the failed engine’s prop and tells it to feather. If all this happens properly then no crew actions are required until you get to a safe altitude. If it doesn’t happen, then the crew must take steps immediately to feather the prop and ensure sufficient power is being supplied by the good engine.
So, that is the background for our trials and tribulations over the course of sim sessions 3, 4, and 5.
We were given constant engine failures just as we are taking off. Initially nothing is said until the flying pilot calls for the gear to be selected up, the non-flying pilot then selects the gear up and announces the engine failure. The flying pilot must then, while struggling to control the aircraft, confirm the failure, and request “power up.” That is the PNF’s cue to check that the good engine has up-trimmed and that the failed engine’s prop has feather. If this hasn’t occurred then the PF must call for the “engine failure recalls” which is the PNF’s cue to feather and shut-down the failed engine from memory, there is no time for checklists at this stage.
Although the PF’s roll is to just fly the aircraft they are also required to confirm each action that the PNF takes as they do the recalls. Unfortunately, until you get good at this sort of thing, as soon as you take your eyes off what you are doing to look at what your mate is doing, the aircraft starts veering wildly, generally searching out the nearest hill or building :).
We crashed on our first attempt, but things gradually got better, it was always a struggle though, through to the end of the training, these engine failures would require full concentration.
As we went on, more complicated failures were given. Engine fires, propellor overspeeds, engine failures with a failed auto-feather. We also had to conduct handflown (no autopilot or flight director) NDB approaches in bad weather followed by a circling approach (basically a low level, bad weather circuit) to land, all with one engine failed. This was probably the most difficult exercise out of everything.
Session four also included failures of other systems such as hydraulics and electrics.
At the end of session 4 the instructors failed both our engines from about 4,000’ overhead the airfield at night. We hadn’t reset the sim properly and the landing gear and flap were still extended from our previous exercise, so the forced landing ended up being a bit of a dog’s breakfast. We crashed on our first attempt, and then got in on the second, but the instructors failed one of the landing gear struts so we careened off the side of the runway and had to go through an emergency evacuation.
More to come.
