If you have an autopilot and FD, if hand flying why not use the FD? It also means you can always activate the autopilot and everything is set up. But if you are just flying along and not using the FD (eg for a visual approach) I always turn it off as it is very disconcerting having a contrary FD indication.
Of course practising on raw data is also important but FDs are very reliable as the main failure mode of autopilots (servos) is removed.
Raw data is just that – no assistance from the FD. Initial type rating skill tests and ATPL skill tests boy require a raw data approach (normally an ILS). Single engine operations are required to be manually flown on checks but with FD assistance.
The basic rule for flight directors is follow them if they are on, if you are not following them switch them off.
There are certain failures where either FDs should not be followed, or are not available – I had one such failure late last year that required 90 minutes of manual, raw data flight including an ILS down to 400’ so they do happen.
FD use and manual flight are a long-running debate in professional aviation as there is a lot of concern that people are too reliant on the automatics and unable to fly accurately without the automatics.
Peter, Raw Data in the airline business is FD off.
Of course if you are flying an Airbus product you can get rid of the FD and select the “bird” or flight path vector, with this you can select a flight path angle, most people use this on an aproach with no vertical guidance because when you get to the TOD and select the FPV it will fly the aproach angle irispective of wind ( and do it quite well ). The big problem with FPV is that if you mis-select it things go wrong very fast, I think it was an AIR INTER flight that the pilots wanted a FPA of 3.3 degrees and mis selected 3300f/m an error that resulted in a tragic outcome.
Myself I prefer to use ground speed and the table on the Jepps to maintain the flight path, at a long deceased UK airline we had a very good system of monitoring the vertical flight path were the pilot monitoring talked the pilot flying down the vertical path and calling errors & corrections ( if required ). After the company when bust two of us got a sim ride with a far eastern company, for the NP approach we reverted to UK SOP but we’re told very firmly that one pilot was not allowed help the other pilot during the NP approach………………. I can think of three occasions on which this company has driven serviceable aircraft into the side of hills and I guess I know why.
I have a FD as part of my AP installation of the Stec 60-2. I rarely ever use it for hand flying, preferring to use raw data. This is mainly because of the relatively poor performance of the FD on the Stec AP. I use the indication of the command bars as feedback that I have the AP on with both a vertical and lateral mode engaged.
Interesting… I would have thought that if the FD is performing poorly, there is little chance of the autopilot working well. The FD is basically a representation of the error signal which the autopilot is supposed to minimise.
That’s another great thing about the DFC90 digital autopilot. The FD is so precise, you feel like in some video game. There’s no lag or anything … The FD is on if the wedges are green, if they are magenta it’s off.
I use my FDs almost all the time.
In the airlines, if PF is hand-flying with the FD on, then PNF or pilot monitoring has to make the heading/altitude/speed/VS selections which does increase his/her workload, so usually PF will take the AP out when the approach is all set up (LOC/GS armed).
I’ve been told by two separate instructors not to use it?
I have been told by instructors …
… to never lean the engine, because it would stop
… to always make power off landings, because otherwise i couldn’t reach the field in case of engine failure
… to fly a little “faster” on approach in the summer because of “thinner air”
… that MoGas would destroy the O-320 of my Warrior
want more? :-)
During my IFR time on the Seneca I used it whenever possible (KFC150). I now had it installed in the Mooney, the first trials I managed to do with it look very good indeed. Also the feedback from the test pilot was very good. (System 55x with Aspen EFD) For myself, I would not want to fly IFR without it unless a specific scenario (such as test flights or checkrides where examiners insist) warrants me to switch it off.
