X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 10 Mar 2014 15:49:51 -0400 Message-ID: X-Original-Return-Path: Received: from mail.rbr3.com ([72.15.229.5] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6768784 for lml@lancaironline.net; Mon, 10 Mar 2014 15:23:14 -0400 Received-SPF: pass receiver=logan.com; client-ip=72.15.229.5; envelope-from=Shane@rbr3.com Received: from RBR-SERVER.rbr3.local ([fe80::61db:2999:1d44:afbf]) by RBR-SERVER.rbr3.local ([fe80::61db:2999:1d44:afbf%10]) with mapi; Mon, 10 Mar 2014 15:17:40 -0400 From: Shane Bangerter X-Original-To: Lancair Mailing List X-Original-Date: Mon, 10 Mar 2014 15:17:40 -0400 Subject: RE: [LML] Re: IV-P Landing Gear Thread-Topic: [LML] Re: IV-P Landing Gear Thread-Index: Ac88dqqR6bWEpD+6RGi0ZsmenKe3hQAFWJ3w X-Original-Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_F86615B51FD0F24B80B59522E5CB0E7B13C0F8931BRBRSERVERrbr3_" MIME-Version: 1.0 --_000_F86615B51FD0F24B80B59522E5CB0E7B13C0F8931BRBRSERVERrbr3_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Lessons learned from my hydraulic landing gear pump failure/seizure and suc= cessful backup procedure gear extension: 1) If the hydraulic pump light c= omes on and stays on during normal flight, to avoid over eating the pump (s= ee Bob's caution below), pull the hydraulic pump circuit breaker until read= y to lower the gear. 2) As current from the pump failure may cause the alt= ernator circuit breaker to pop, reset the alternator circuit breaker if nec= essary after pulling the hydraulic pump circuit breaker. 3) If the gear wi= ll not lower with the normal procedure, follow the backup landing gear exte= nsion procedures: slow airplane to 120 kts., test gear lights, pull hydrau= lic pump circuit breaker, lower gear handle, activate accumulator or hand p= ump, yaw aircraft and increase positive Gs if necessary to get three green = lights and land as soon as practical even if you don't have three green lig= hts. 4) Replace the gas strut to the nose gear annually. 5) Practice the e= mergency gear extension procedures in flight which will verify the system, = including the gas strut, is working properly. 6) Review all emergency pro= cedures regularly, and 7) Annually train with a LOBO approved or like instr= uctor. Shane Bangerter 89GG IVP 320 hrs. From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Will= iam A. Hogarty Sent: Monday, March 10, 2014 10:41 AM To: Lancair Mailing List Subject: [LML] Re: IV-P Landing Gear Bob: Nice article on the IV landing gear operation. I would like to stress the importance of the monthly inflight check of th= e system and the necessity of replacing the nose gear gas actuator during e= ach annual. (don't rely on a ground retraction test) If you have an electrical failure, the gear will drop as you point out BUT = if the nose gear gas actuator is not fully pressurized (100 psi), the nose = gear will appear down but there is a strong possibility that the linkage d= oes not go overcenter and lock. Without electrical power, you will not hav= e your gear indicator lights to warn you. (don't ask how I know) Keep up the good work. Best regards, Bill Hogarty On Mon, Mar 10, 2014 at 6:48 AM, Robert R Pastusek > wrote: Gentlemen, Without reflecting on the cause of the most recent IV-P loss, I was asked t= o review the operating principles of the Lancair IV landing gear system for= those of you that did not build your airplane. Hopefully this knowledge wi= ll help you if you should have difficulty with the landing gear--which, by = the way, has a different operating principle from the Legacy and 3-series a= ircraft. The landing gear in the IV-P is hydraulically operated by an electric power= pack (a pump/reservoir assembly commonly used to control boat lift/tilt ou= t-drives). Hydraulic fluid is circulated from the pump to a gear/flap contr= ol on the center vertical instrument console in the cabin. The gear handle = is actually a hydraulic valve that switches fluid flow between the "up" and= "down" sides of hydraulic actuators that are attached to the two mains and= the nose gear. With the landing gear handle in the UP position and the hydraulic system pr= essurized, all three gear are retracted and held up by the pressure. There = are no up-latches. If you lose hydraulic pressure in the system for any rea= son, the mains will "free-fall" to a partially-extended "trailing" position= but will not fully extend because they must move forward (against an air l= oad) to do so. NO AMOUNT of maneuvering, touch and go, or flying around wil= l fully extend the mains, and they WILL fold back into the gear bays at tou= chdown if partially extended. No exceptions. The only way to fully extend t= he gear is to apply hydraulic pressure to them, either by restoring the ele= ctrical pump to normal operation, or by use of the hand pump between the fr= ont seats to manually pump fluid into the main gear actuators. There are se= veral things that need to work correctly for this to happen, so emergency g= ear extension--both on jacks and in-flight-- should be one of your required= condition inspection items. The nose gear is equipped with an air spring that causes it to extend fully= if hydraulic pressure is lost. Once extended, it can only be retracted by = restoring normal hydraulic pressure with the gear handle in the up position= . The emergency pump applies pressure only to the down side of the main act= uators; it does not supply fluid to the nose gear actuator in any circumsta= nce. So to repeat, with a loss of hydraulic pressure, you'll get an "automa= tic" nose gear fully extended, and "trailing" mains. The hand pump should b= e able to fully extend the mains, allowing them to lock down automatically,= but if it doesn't, the mains WILL retract on landing. There are no known a= lternatives or exceptions. By the way, if you can get the mains fully exten= ded (green down lights), the actuators have built-in locks that should hold= them fully extended, even if hydraulic pressure to the actuators is subseq= uently lost. Even so, if one or both of the main gear indicator lights shou= ld go out, consider a final tug on the emergency pump just before landing. = If it can be pumped, do so; if it doesn't move, you should still have fully= extended mains. For me, any un-commanded extension of the landing gear would be time to put= the airplane on the ground and sort out the electrical and/or hydraulic pr= oblem--for several reasons. As an example, a hydraulic leak can dump all th= e fluid overboard quickly, and allow the pump to run continuously. In time,= it will destroy itself, and has been known to catch fire--it's not designe= d for continuous operation. One other thought. Flying by the tower, or even having another airplane loo= k you over for extended gear is probably a waste of time, and may give you = a false sense of security. Unless the observer is familiar with the IV lan= ding gear system, he/she is unlikely to identify the difference between mai= ns that are fully extended forward and those in the trail position. They wi= ll note that the nose gear looks good (it should be), conclude that the mai= ns are also "extended," and report that. Lastly, the gear handle has an electro/mechanical "lock" built into it that= SHOULD prevent it being moved out of the down position when the airspeed i= s below about 90 Kts (this is adjustable, so it could be more or less). If = you move the handle to UP when the airplane is on the ground and the hydrau= lic system is pressurized, the weight of the aircraft SHOULD prevent the ma= ins from retracting, but the nose gear will definitely retract, dumping the= nose and prop on the ground. Your checklist does require you to check that= the gear lever is in the down position before applying power to the aircra= ft, doesn't it? Landing gear malfunctions are serious, and can result in major damage to yo= ur airplane even in the best of circumstances. They should not, however, ki= ll or injure you or your passengers if you apply your training and keep you= r cool. Lancairs fly well in any known landing gear configuration. So task = #1 is always to fly the airplane to the scene of the crash...always. I'd be pleased to talk to any of you either on- or off-line about this. Jus= t drop me a note. Bob Pastusek --_000_F86615B51FD0F24B80B59522E5CB0E7B13C0F8931BRBRSERVERrbr3_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Lessons learned = from my hydraulic landing gear pump failure/seizure and successful backup p= rocedure gear extension:  1)  If the hydraulic pump light comes o= n and stays on during normal flight, to avoid over eating the pump (see Bob= ’s caution below), pull the hydraulic pump circuit breaker until read= y to lower the gear.  2) As current from the pump failure may cause th= e alternator circuit breaker to pop, reset the alternator circuit breaker i= f necessary after pulling the hydraulic pump circuit breaker.  3) If t= he gear will not lower with the normal procedure, follow the backup landing= gear extension procedures:  slow airplane to 120 kts., test gear ligh= ts, pull hydraulic pump circuit breaker, lower gear handle, activate accumu= lator or hand pump, yaw aircraft and increase positive Gs if necessary to g= et three green lights and land as soon as practical even if you don’t= have three green lights.  4) Replace the gas strut to the nose gear a= nnually. 5) Practice the emergency gear extension procedures in flight whic= h will verify the system, including the  gas strut, is working properl= y.  6) Review all emergency procedures regularly, and 7) Annually trai= n with a LOBO approved or like instructor.

 

Shane Bangerter

89GG IVP 320 hrs.

=  

 <= /o:p>

From: Lancair Mailing List [mai= lto:lml@lancaironline.net] On Behalf Of William A. Hogarty
Sen= t: Monday, March 10, 2014 10:41 AM
To: Lancair Mailing ListSubject: [LML] Re: IV-P Landing Gear

 

Bob:=

 

<= div>

Nice article on the IV landing gear operation.&nbs= p;

 

 I would like to stress  the importanc= e of the monthly inflight check of the system and the necessity of rep= lacing the nose gear gas actuator during each annual.  (don't rely on = a ground retraction test)

 

If you have an electrical= failure, the gear will drop as you point out BUT if the nose gear gas actu= ator is not fully pressurized (100 psi), the nose gear will appear down but= there is a strong  possibility that the linkage does not go overcente= r and lock.  Without electrical power, you will not have your gear ind= icator lights to warn you.  (don't ask how I know)

 

Keep up the good work.

<= o:p> 

Best regards, Bill Hoga= rty

 

On Mon, Mar 10, = 2014 at 6:48 AM, Robert R Pastusek <rpastusek@htii.com> wrote:

Gentlemen,

Without reflecting on th= e cause of the most recent IV-P loss, I was asked to review the operating p= rinciples of the Lancair IV landing gear system for those of you that did n= ot build your airplane. Hopefully this knowledge will help you if you shoul= d have difficulty with the landing gear--which, by the way, has a different= operating principle from the Legacy and 3-series aircraft.

The landing gear in the IV-P is hydraulically operated by an = electric power pack (a pump/reservoir assembly commonly used to control boa= t lift/tilt out-drives). Hydraulic fluid is circulated from the pump to a g= ear/flap control on the center vertical instrument console in the cabin. Th= e gear handle is actually a hydraulic valve that switches fluid flow betwee= n the “up” and “down” sides of hydraulic actuators = that are attached to the two mains and the nose gear.

With the landing gear handle in the UP position and the hydraulic = system pressurized, all three gear are retracted and held up by the pressur= e. There are no up-latches. If you lose hydraulic pressure in the system fo= r any reason, the mains will “free-fall” to a partially-extende= d “trailing” position but will not fully extend because they mu= st move forward (against an air load) to do so. NO AMOUNT of maneuvering, t= ouch and go, or flying around will fully extend the mains, and they WILL fo= ld back into the gear bays at touchdown if partially extended. No exception= s. The only way to fully extend the gear is to apply hydraulic pressure to = them, either by restoring the electrical pump to normal operation, or by us= e of the hand pump between the front seats to manually pump fluid into the = main gear actuators. There are several things that need to work correctly f= or this to happen, so emergency gear extension--both on jacks and in-flight= -- should be one of your required condition inspection items.

The nose gear is equipped with an air spring that causes it= to extend fully if hydraulic pressure is lost. Once extended, it can only = be retracted by restoring normal hydraulic pressure with the gear handle in= the up position. The emergency pump applies pressure only to the down side= of the main actuators; it does not supply fluid to the nose gear actuator = in any circumstance. So to repeat, with a loss of hydraulic pressure, you&#= 8217;ll get an “automatic” nose gear fully extended, and “= ;trailing” mains. The hand pump should be able to fully extend the ma= ins, allowing them to lock down automatically, but if it doesn’t, the= mains WILL retract on landing. There are no known alternatives or exceptio= ns. By the way, if you can get the mains fully extended (green down lights)= , the actuators have built-in locks that should hold them fully extended, e= ven if hydraulic pressure to the actuators is subsequently lost. Even so, i= f one or both of the main gear indicator lights should go out, consider a f= inal tug on the emergency pump just before landing. If it can be pumped, do= so; if it doesn’t move, you should still have fully extended mains. =

For me, any un-commanded extension of the lan= ding gear would be time to put the airplane on the ground and sort out the = electrical and/or hydraulic problem--for several reasons. As an example, a = hydraulic leak can dump all the fluid overboard quickly, and allow the pump= to run continuously. In time, it will destroy itself, and has been known t= o catch fire--it’s not designed for continuous operation.=

One other thought. Flying by the tower, or even having an= other airplane look you over for extended gear is probably a waste of time,= and may give you a false sense of security.  Unless the observer is f= amiliar with the IV landing gear system, he/she is unlikely to identify the= difference between mains that are fully extended forward and those in the = trail position. They will note that the nose gear looks good (it should be)= , conclude that the mains are also “extended,” and report that.=

Lastly, the gear handle has an electro/mechan= ical “lock” built into it that SHOULD prevent it being moved ou= t of the down position when the airspeed is below about 90 Kts (this is adj= ustable, so it could be more or less). If you move the handle to UP when th= e airplane is on the ground and the hydraulic system is pressurized, the we= ight of the aircraft SHOULD prevent the mains from retracting, but the nose= gear will definitely retract, dumping the nose and prop on the ground. You= r checklist does require you to check that the gear lever is in the down po= sition before applying power to the aircraft, doesn’t it?=

Landing gear malfunctions are serious, and can result in = major damage to your airplane even in the best of circumstances. They shoul= d not, however, kill or injure you or your passengers if you apply your tra= ining and keep your cool. Lancairs fly well in any known landing gear confi= guration. So task #1 is always to fly the airplane to the scene of the cras= h…always.

I’d be pleased to talk = to any of you either on- or off-line about this. Just drop me a note.

Bob Pastusek

 

= --_000_F86615B51FD0F24B80B59522E5CB0E7B13C0F8931BRBRSERVERrbr3_--