Upgraded Question - Do you Feel Confident you can Fly a Circuit with a Failed ASI

[SSCBD]

With the glass cockpits on these RAA coffee machines these days, what happens IF the system fails or power shuts it down. Or the old steam ASI needle falls off. Just to cover the bases.

 

Can you be confident say in gusty weather (and say a 15kt crosswind to be sporty) to fly a circuit and land with NO reference to any instruments. (and no cheating by putting your thumb out the window - smile)

 

NOT suggesting anyone try this without an instructor whatsoever.

 

 

[kasper]

Yep. Would be perfectly happy doing that in vmc within the limits of the aircraft.

 

I fly by attitude and the asi is a check instrument not the focal instrument.

 

 

[SDQDI]

Well with that amount of crosswind and being gusty I would still be happy enough BUT I would use a lot less flap (if any) and err on the quicker side just to be safe. I wouldn't be as happy if I was using a super short strip though.

 

 

[Old Koreelah]

During our training we've all had the instructor cover up the gauges, haven't we? Stick position, feedback from the controls and noise level are all our ancestors had.

 

 

[nomadpete]

In the Gliding world (don't they fly in the same air as us?), I didn't get to go solo until I could do a safe circuit & landing with ASI and Altimeter covered up.

 

 

[geoffreywh]

is your rev counter working?

 

 

[frank marriott]

During our training we've all had the instructor cover up the gauges, haven't we? Stick position, feedback from the controls and noise level are all our ancestors had.

I believed that to be the case until flying with RAA over a period of 10yrs and now have the realisation that it not always the case. The situation is obvious that there is a BIG variation in training from one RAA school to another.

 

Not fair to generalise but SOME outputs are at best basic.

 

 

[Possum1]

This happened to me for real in an elderly C182L that I was using for my scenic flights about 15 years ago, which had a pitot tube with one of those flip-flop bug deflectors on the front of it. It jammed at about 45 knots and I persisted with the take-off(wrong decision) thinking that the extra airflow when I accelerated to cruise speed would open it out fully. It didn't. I then flew the plane on the tacho and did quite a nice landing and parked close to my car. I then got a can of WD-40 out of the boot and thoroughly sprayed the offending flip-flop and then proceeded with the pax on my scenic flight.

 

 

[Gibbo]

I've met with a wasp in the pitot tube up at emerald. ASI seemed to work fine until about 50kn then nothing more.

 

I chose a fast landing speed and thankfully I was fairly current at the time and was used to 'normal attitudes and handling'. Having a nice long strip takes the pressure off as well.

 

 

[The Therm]

Instructor got me to do just this last week in the Tecnam, no crosswind component but a great exercise to just 'feel' the aircraft.

 

 

[HonkyNerdPilot]

Yep, I did a couple of circuits on a 172 with airspeed covered up. As long as I have the tach and a good horizon I am confident that I will be within 5 knots of approach speed. I always fly final approaches with attitude like any other part of flying, in fact the flight school where I got my RPL in really emphasised that and I am super grateful that they did.

 

 

[kaz3g]

Yes....gusty and 15 knot cross wind I'd be too busy flying the aeroplane to worry about what the ASI said.

 

Fly the attitude --- or at least try to

 

Kaz

 

 

[Guernsey]

It's like a lot of things in life, if you have the right attitude all is well.

 

Alan.

 

 

[Head in the clouds]

I'd seriously suggest that anyone who has any doubts about whether they can complete any part of a flight (i.e. all of the flight - takeoff, climb-out, cruise, approach and landing) without an ASI, might spend a bit of time practicing. At the very least take a sticky card disc along on your next BFR and get your instructor to use it to cover the ASI for a few complete circuits, you'll be surprised how well you can do without the ASI when you have to. It'll give you more confidence to handle the situation when the day comes that a bug blocks your pitot - it does happen, my first one was a part of a grasshopper when I unwittingly flew through a plague of them.

 

On the same subject, it's quite surprising what instrumentation you can manage without when you have to - even more so with a bit of practice beforehand. That practice allows you to recognise other influences which provide clues for filling in the gaps.

 

In helicopters one of the most feared instrumentation losses is the rotor tacho. You're supposed to keep the rotor rpm at 100% pretty much all the time and the knowledge that 104% imposes almost double the centrifugal loading (IIRC it's about an extra 40 tonnes per blade on a Jetranger ...) and anything over 104% brings on a red light on the panel which can't be extinguished for less than about $80,000 due to required replacements of overstressed components.

 

And - there's the opposite scenario, where a 6-8% droop of rpm in autorotation allows the blades to cone upward and is borderline on ever being able to recover.

 

On one occasion I was flying a KH4 (Kawasaki-built 4 seat variant of the Bell 47) when the rotor tacho needle dropped to zero. I was happy that the KH4 is a piston machine and consequently has two needles on the same instrument, the other being the engine rpm (they have both needles overlaid so that you can see whether drive belts, or the sprague clutch might be slipping/failing, and the like). I mentioned to my passenger (the owner of the aircraft) that we'd have to make an immediate landing if the other needle failed, as it was the only information I had left, from which to form opinion about the rotor rpm. Typically, that second needle then also dropped to zero.

 

The aircraft owner was/is a very 'insistent' type who wouldn't hear of landing in remote bushland 30 miles or so from any settlement, so I bit the bullet and concentrated hard on the 'sound' of the rotors and engine and it quickly became apparent that I could detect the change in sound with increase and decrease of rpm better than I'd ever noticed before. Nonetheless I was happy to get on the ground half an hour later.

 

But that wasn't the end of it. On arrival we found that the owner's 2yr old had fallen gravely ill and, after consultation over the HF, had to be transferred to hospital urgently. It was a 4-5 hour 4WD drive on very rough tracks or about 40mins by helicopter. I had no choice but to declare a mercy flight, refuel and get on with it. Once I knew I had to ignore the lack of rpm indication, it became quite easy to just fly to the familiar engine note and rotor beat.

 

Following that I made a habit of relying less on the tachos and more on my 'senses' and using the instrument to check on myself, rather than to monitor quite so regularly - and that reduced my workload a little, providing more time for other needs.

 

 

[Phil Perry]

Yep. Would be perfectly happy doing that in vmc within the limits of the aircraft.I fly by attitude and the asi is a check instrument not the focal instrument.

I am GLAD that you are around to keep a sense of perspective in this regard Mr. Kasper Sir. . . .Being 3 axis trained from an early age ( 7 ) and having an old Mainair Geminii Flash2 as well ( 1300 hours in that one ) Flying by attitude comes naturally now. OK if I was flying an Airbus A 321 or B 777, then I would defer to the flight manual. . . but there is a lot of tosh spoken about glueing ones eyes to the ASI, when you should have your head up keeping a good lookout. . .