Paphitis wrote:bigOz wrote:Paphitis wrote:bigOz wrote:OK a simple emergency question for all the would be pilots and pilots! I want to see who will come up with the answer first!
Although he completes the external checks and everything is fine, A student pilot is so excited that he takes off without carrying out his pre-flight checks. He is about to do some circuits that would involve touch and go's. As he turns downwind round a left circuit, he is having to fight the controls to keep the aircraft in straight flight. Aircraft keeps wanting to roll left. As he turns for the final approach, the aircraft's controls start getting stiffer and stiffer and he is physically having to exert excessive force on the controls to stop the aircraft from rolling left, and possibly stalling.
He just about manages to land the single angine aircraft safely using some the learned skills, only to find out what was the problem soon after.
a) what actions he took to land the aircraft safely and without stalling?
b) what could have caused the aircraft to behave in such a potentially fatal manner?
He/she did not remove the Pitot Tube cover and didn't have any airspeed indication. His Rudder Trim was possibly not set in the neutral position and his airspeed was low enough to make the aircraft want to stall and enter an incipient spin.
Recovery is power up and nose down to increase airspeed and airflow over the left wing and apply right rudder.
He she probably didn't dip the tanks and so the aircraft may have been left wing heavy. This is just a minor factor!
Thanks for trying Paphitis! Also thank you for your other detailed replies.
Your answer to the above incident for part (a) is correct! The action would provide what we would call a 'skid' and allow the aircraft touch down safely - albeit with full rudder, a lot of forward pressure on control column and increased power to maintain the correct glide path.
The answer to part (b) for this actual incident at an Airfield in UK (by a close associate many moons ago) was in fact due to incomplete pre flight checks!
The person in question did not bother with checking the state of the auto pilot. It should always be OFF during take off and in a circuit. On this occasion it was left ON by ground crew who checked the power to the navigational instruments. Autopilot was tuned to a nearby VOR and it kept trying to roll towards its direction. Beacause of the terrain take off and crosswind legs were unaffected.
For crying out loud BigOz, why didn't you just tell me that the aircraft had and AP?
I had assumed that there was no 3 axis AP, because the kid would've been flying something light like a C152/C172 for example and most don't have APs.
Kikapu wrote:I have couple of questions to Paphitis and BigOz.
I have never flown with a AP, so I don't know what happens when the pilot comes and turns everything electrical on to go for a flight. I only had "trim tap" adjuster to help fly with less effort on the yoke.
If the AP was left ON from previous flight, but all electrical systems were turned off, would that not then disengage the AP automatically, or would the AP remain ON when the next pilot comes along for a flight, turns on the electrical system, and then takes off without the take off check list. The question is, does the AP needs to be turned off manually before all the electrical system is shut down, so that when the next pilot turns on the electrical system on, that the AP also remains OFF.
Some older light aircraft have only very basic AP. It can be just a little switch which makes the aircraft roll Left or Right and enter a Climb or Descend. There is no Auto throttle or Altitude Hold. There usually is a Heading Hold coupled to the Heading Bug which you set on the Horizontal Situation Indicator (HSI). More advance AP, can be coupled to Track TO or From a VOR, maintain a Localizer (LLZ) and Glide Slope for an Instrument Landing System Approach. Most light aircraft don't have this level of automation, unless they are IFR category.
If the Auto Pilot is left on but the Master is turned OFF, and then subsequently when another pilot comes along and turns the Master, the AP would be ARMED and there should be an AP red light on the Annunciator Panel directly in front (or to the side) of the pilot. The AP is merely ARMED but will not track on anything until it is instructed to either maintain a Heading (HDG) Bug, or maintain a VOR, LLZ and Glide Slope, or Climb and Hold a particular Altitude. I will try and not get ahead of myself, because most light aircraft will only have a HDG Hold AP. The light aircraft that BigOz mentioned was coupled to a VOR and therefore aircraft kept wanting to turn towards the station.
Therefore, the AP could be ON and ARMED but not tracking or holding anything. It is on Standby. If the HDG bug switch is ON or the VOR switch is left on, then the AP will want to turn and intercept the set Heading on the HSI or turn to intercept the set Track TO or FROM the set VOR navigation aid.
Kikapu wrote:BigOz stated that it was the mechanic that had left the AP ON, so, does that then mean that the pilot took the plane from the mechanic while all the electrical system was already running, which may explain that the AP was still in the ON position..??
There are a few things that don't quite add up.
For example, even if the AP was engaged and it is coupled to a VOR, then the pilot is EASILY able to overpower the AP. The AP can be set to anything, but a Pilot is still able to place his hands on the yoke and make any control inputs whatsoever regardless on whether the AP is ON or not. So I still don't really understand what BigOz is trying to say really. The AP would not have been an issue at all!
Also, there is an AP disengage toggle on the Yoke next to the Press To Talk (PTT) and Electric Trim switches. This is standard. The pilot should have noticed the Annunciator Indications and pressed the A/P disengage!
Kikapu wrote:Also, are there no indicators anywhere on the dash board that shows the AP is activated in ON position.?? If there is one, how come this pilot did not see that the AP was activated, which was causing him the problems.
Yes, there most certainly is.
There is an Annunciator Panel, and this would have indicated if the AP was Armed. If it was set to a heading Bug, then a HDG symbol will also appear on the Annunciator Panel. If it was coupled to a VOR, then either a VOR or NAV symbol will also appear on the panel. If it was coupled to an ILS, then an LLZ and GS symbol will appear on the panel!
Kikapu wrote:I have a hard time to believe, that anyone who goes for a flight, experienced or beginner, that they did not go through the check list.!!
Me neither.
The instructor that signed him off would have ensured that the student pilot was well drilled in completing ALL checklists.
There are certainly many questions left unanswered by our dear friend BigOz!!!
Kikapu wrote:On a side note, when my flight medical was active many years ago, I would receive from the FAA quarterly( I think) safety news letters with real case scenarios as what BigOz described. They were very educational to know what silly mistakes can be made by pilots as well as problems with the aircraft, and to look out for them. As I've said, they were very educational.
If your Student Pilot Licence is still active and an ARN, then you should still be receiving these. Give the FAA a call and find out.
In Australia we get a magazine (Journal) published by CASA called Flight Safety.