Gear Warning Horns -How loud is yours
 

Understand an Essendon Seminole VH-ZWI landed wheels up at Point Cook last week. Happens to the best of us. Understand that this particular aircraft gear warning horn was very weak in volume. Is this common in most PA 44's ?

Assessment of the loudness in stall warning as well as gear warning horns, is subjective - depending on how deaf you are. I doubt if the horn efficiency is checked as part of routine maintenance while at the same time not many people think of defecting these in the maintenance release. Might save someone from a wheels-up one day.

On some A/C, under certain conditions of speed/power lever (or throttle)/flap position the horn may be temporarily cancelled (ie practice asymmetrics).

Any possibilities along this line??

One particular A/C I remember (BE76) has a stall warning which sounds the same as the gear warning. This has serious potential.

I remember one day when we were turning base (asymm, still with the gear up) and Bloggs reduces power on the live engine to below the trigger level for the gear horn. Horn blaring away, I ask him what that could possibly be?

"We are stalling, sir. But it's okay, we have 95 knots".

Next!

He did well to remember the 'sir' under the 'g' that must have been present! :rolleyes: :D

Centaurus you seem to ask many questions for somebody who is seemingly so knowledgable in all things aviation. How did you get to be so good.

For once can you not offer some advice commensurate to your vast experience.:eek:

An aircraft I had once had an illegal automotive speaker fitted - could hardly hear it. Engineer insisted on fitting the correct item - at aviation price of course. Some owners might be very tempted to do the wrong thing on these 'non-essential' items at times.

Re: Gear Warning Horns -How loud is yours
 

Centauraus

Your guess is wrong. When up on jacks doing retractions and throttle/flap configuration warnings are tested, the gear warning horn is something "maintenance" are looking at/listening to. That's what they are there for. At least while I am in charge they bloody well are! What's the point of doing the farkin functional otherwise?

If it sounds like a sick cow, change the farkin thing!!
If you can't hear it over the sound of the hydraulic rig, how the hell is a driver gonna hear it over the scream of a coupla vacuum cleaners on the wings?

For those electric beasties, same thing. If it is only just audible in a silent cockpit, common sense prevail pleeeease!

I think I need a quiet lie down. :(

Had a PA31-350 with an aural verbal warning through the headset. Didn't believe it at first so had to have a play, in the gear horn situ "warning check wheels (or something likr that)"

Now if we were all in the RAAF we wouldn't need to worry
TWR" Viper 21 check wheels"
VPR "Viper 21 three greens"

If you want an interesting read, check out

http://www.atsb.gov.au/aviation/pdf/vh-inh.pdf.

It's the 1996 final report on the Ansett 747 accident at YSSY. Gear warning horn features very prominently.

High Altitude, you would need to worry if Viper happened to be a 747. Three greens not nearly enough, not even four as was called on the Ansett 747. Now if they had seen five...............!

Hugh Jarse,

I've flown about 5 different duchesses and they all have an intermittant squark for the gear as opposed to the continuous squeal of the stall...

Lancer

Along similar lines but probably more relevant to charter pilots is "When does your gear go off?"

On the piston twin I fly, the manufacurer states the gear warning horn on should be set to sound at 11" manifold pressure. My IO-520s never get below 15" MP until the flare....

Maybe maintenance organisations whould consult with the company SOPS for engine handling and set the horns a little higher?

Food for thought.

Centaurus

Your statement "happens to the best of us " must surely be a contradiction. "The best of us" follow procedures and checklists as a vital part of their day to day working lives. Clearly landing with undercarriage in the retracted position indicates that the appropriate checklist/procedure was not completed.
Those that have allowed this to happen may once have been able to lay claim to the "best of us" however they obviously were mistaken, and can no longer.

******** statement sport.

I once flew a light twin (can't remember if it was a Seminole or Duchess) where after a few minutes (such as in asymmetric training) the gear waring horn suddenly went quiet, as if it was being strangled. I guess it just ran out of breath!

Mention 1.
Thanks for that post. Now that I find very interesting and will keep that in mind. What can happen is that during an asymmetric circuit with one engine set at zero thrust (usually about 11.5 MP in Seminole/Duchess types), the U/C horn sounds.
I have seen people then nudge that throttle up a tad to stop the horn from sounding. There goes one safety net.

Then on final some prefer to use minimum flap (for go-around capability) and unless the flaps are set beyond a certain setting, the gear horn will not sound either. There goes the second safety net.
If significant power is used on the live engine until the flare, the horn may not sound until into the flare.

Way back in the mists of time a DCA Avro 125 did a wheels up landing at Avalon with two DCA Examiners aboard . It was on a flapless, necessitating low thrust lever settings and the pilot silenced the horn late downwind. The thrust levers being almost at idle on base and final were such that the horn never re-armed. A very smooth belly landing resulted.

On another incident (well, almost), involving a practice asymmetric at Canberra in the first of the RAAF's Avro 748's, a wheels up landing was averted by the alert QFI (takes modest bow and awaits tumultuous applause in Pprune pages).

The 748 had the usual horn warnings attached to the throttles and flap positions. But it also had a dinky little device in the face of the ASI. If the aircraft got below a certain speed on final with gear still up, the word U/C displayed itself and flashed. You could never miss it. Never?? Don't you believe it. The student undergoing endorsement training was downwind with one on zero thrust (Rolls Royce Dart engine). Student distracted by noise of horn and pushes horn silence button. Delete first safety net.

Told to extend downwind due someone else long final, therefore delays lowering of gear. Good thinking 99. Eventually turns base and starts descent but with plenty of power on live engine due long way out.

Forgets to call for gear. QFI twigs to this and keeps eye on things. Eventually student calls for landing flap and off goes the horn real loud. Student concentrating on glide path and ignores (or never hears) horn. QFI now wide awake and watching with great interest the unfolding drama.

At 600 ft on final with gear up, full flap and around 100 knots, the ASI U/C warning flag starts to flash urgently (the one that you can't miss!). Student looks right through it as he tries to pin the airspeed. QFI now watching a life lesson in how a pilot can somehow be concentrating so much that he misses all the obvious signs of a potential gear up landing.

Finally QFI orders a go-around on both engines (easy enough because one was set at zero thrust and not feathered). Student opens up power and calls for gear up. QFI tells him to pull his own gear up. Student reaches across to gear lever and is dumbfounded to see the gear lever is already up.

I would never have believed this could have happened given the various safety nets for gear operation in the 748. But it did.

Interesting too, is the common flying school dogma of teaching ab-initio students to call Undercarriage Down and Locked in fixed gear aircraft on the premise that one day the student will go on to a retractable and that it is a Good Thing - even though it does not apply to a fixed gear Cessna/Warrior - nor is it called for in the manufacturer's POH. This policy is yet another of the myths taught in GA. Interesting too, that the RAAF do not teach the mythical gear down policy in their earlier CT4 trainers but wait until their trainee pilots go on to the PC9 retractable.

My understanding is that the retractable gear aircraft is a specific rating and that is where the student should be taught the new extra check of gear position and not before. One can speculate how many of those who have had the unfortunate experience of forgetting to lower their wheels were earlier taught the superfluous Gear Down check during their ab-initio training on fixed gear aircraft. ;)

Centaurus,

Some modern aircraft such as B350 have the gear horn silence button mounted on the left power lever knob. With flaps UP or APPROACH and gear UP the horn will sound below 85%N1 but may be silenced. Once the flap lever is mover towards LAND (there are no intermediate positions) the horn cannot be silenced regardless of throttle setting. Although the aircraft is an excellent performer on one engine, selecting full flap unless landing is assured or unless the aircraft is on a stabilised approach, may require considerable power from the live engine to achieve the aim point! An easy trap for a VMCA type scenario.

All our pilots use the horn silence switch to stop the passengers getting jumpy. And this means every power reduction from FL350 down. Naturally with an adjustment every few thousand feet it becomes second nature so other disciplines are incorporated into SOP’s to ensure the landing gear is always down for the landing!

The method used is to always select gear down just prior to turning base (or one dot below glide path on ILS). The increased drag is offset by the descent and no power change should be necessary. As a check, descent below circuit height is not commenced without three greens. Bearing this in mind the pilot may only need two power settings for entering downwind, one for two engines and a slightly higher setting for one engine. Both settings will achieve 120 KIAS subject to weight. Flaps are selected to approach entering downwind. Vfe – 202 KIAS and Vlo – 184 KIAS so they act like speed brakes to achieve gear speed. By setting the power, airspeed and rate of descent are monitored during base and finals. If either are outside the parameters then gear will probably be the culprit. Landing flaps are used in two engine ops as ‘appropriate’ or asymmetric ops at the minima to achieve Threshold Speed. The ‘appropriate’ position for normal ops is usually 400 – 500 feet. In either case power is reduced to idle at about 50 feet with touchdown on the 1000 ft markers.

The technique is highly disciplined and demonstrated during route checks and proficiency checks. It becomes second nature.

We used the technique many years ago when operating turbo-charged pistons. The gradual power reduction to touch-down followed by maximum use of the runway and backtracking allowed a good rundown of the turbo-chargers. We operated those aircraft over many thousands of hours without a problem.

:) Comp Stall

From memory (and it has been a while) the ginger beers that looked after our piston fleet set the gear horn at 18" MP. Not sure if that was the manufacturers recommendation or one that they used in light of the fact that any piston twin driver worth his salt will not be using less than 15" MP until the flare. Seems bloody pointless having it set to 11" MP. If I was you mate I'd be looking into that and getting something done about it. Given, when the flaps are selected past half it should also sound but what if there is a problem with that switch and nothing happens.

Good thread this one..........somewhat refreshing:).

Onya

As an Instructor I get very frustrated. Pilots are their own worst enemy.
Piper singles used to have an automatic gear extension system.
When speed reduces below a certain speed power combination the gear will extend and when it increases above a certain setting it will retract. One would think "a perfect backup system if the pilot forgets or is distracted"
Guess what: Some pilots, in the States I believe, flew the thing with the gear selector in the up position and let the machinery do the thinking and work.
Guess what: Sometimes the machinery fails.
Guess what: The manufacturer and their Authority decide, in their wisdom, that the best way to fix the problem is to direct owners to remove or disable the automatic.
Makes perfect sense. Some engines do fail sometimes - so lets remove them, because we can't teach the drivers to use them properly.
Back to the topic.
Many years ago there was a gear up landing on a secondary aerodrome. The tower was calling the pilot to go around, but the pilot didn't. Afterwards he was asked why he did not follow the Tower's instructions. He said that he could hear the Tower talking to him but he could not understand what he was saying "because something was making a very loud racket". I suppose that gear worning was TO LOUD.

I remember flying a Be36 and for a while (many trips back to the LAME) the gear warning would sound while in cruise! :o Great for the pax. It wasn't because I was so high that the MP was less than 13" (I think, I have a terrible memory) even with the throttle fully in, but was from the fact the horn is set to sound when the throttle is pulled out a certain distance. In this case the thing was basically stuffed, so even at full throttle, all you had to do was jiggle it and the horn would either sound or stop! :eek:

This is like every machine I have flown, if you ignore that landing flap with gear up will sound the horn, it isn’t a set number be it MP, Torque or N1 that will sound the horn, but PLA.

As for how loud is the horn, he/she can get very loud! “Are you going to drop the gear soon?” :D

Centaurus recalls the 125 wheels up ... two additional comments ..

(a) in a part defence of the chaps concerned, they were screwed around by a Mirage in the circuit with a problem

(b) the funny thing was that the operator had been trying for a long time to get funding approval to mod the beast from a -1A to a -3A (-1B to -3B ? the memory is not 100%) without success .... Guess what ? ... much of the mod was in the belly area .... the prang proved quite serendipitous in that the repairs included the upgrade ....... didn't do much for the crew's ego ... but we guys back at base thought it was pretty good luck ....