Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

GRT GPS TSO

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Mon Jan 08, 2007 8:50 am Post subject: GRT GPS TSO

1/8/2006



Hello Bret, You quote GRT as writing: "The new RAIM-equipped version 

provides integrity

monitoring and 5 updates per second to meet the requirements of IFR GPS TSO 

C129 and C146."



This sounds like some subtle weasel wording to me. A piece of equipment 

either meets the full TSO requirements and is marked TSO compliant or it is 

not TSO'd.



The manufacturer does not get to cherry pick certain standards within the 

TSO, or its references, just meet certain standards, and then mark the 

equipment as TSO'd.



Most manufacturers who have gone to the expense and effort of obtaining TSO 

approval for a piece of equipment are very eager to make that approval and 

marking very evident to any prospective purchaser.



OC -- The best investment we will ever make is in gathering knowledge.



On 5 Jan 2007, at 22:05, Bret Smith wrote:



 	  Quote: 	
		   <smithhb(at)tds.net>



 See http://www.grtavionics.com/documents/Horizon%20System%20Flyer.pdf



 "The addition of the internal GPS receiver eliminates the need for an

 external

 GPS, or may be used as a backup to your primary GPS. Available in two

 versions. The standard WAAS GPS module is perfect for VFR use, or

 as backup

 to an external GPS. The new RAIM-equipped version provides integrity

 monitoring and 5 updates per second to meet the requirements of IFR

 GPS

 TSO C129 and C146."



 Standard WAAS GPS Receiver with antenna $450

 RAIM-Equipped WAAS GPS Receiver with antenna $750

 Bret Smith

 RV-9A (91314)

 Mineral Bluff, GA

 www.FlightInnovations.com

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Bill Denton

Joined: 10 Jan 2006
Posts: 97
Location: Chicago, IL USA

Posted: Mon Jan 08, 2007 9:35 am Post subject: GRT GPS TSO

"A piece of equipment either meets the full TSO requirements and is marked

TSO compliant or it is not TSO'd."



True, but not necessarily the point...



In some instances the regs require that a piece of equipment MUST MEET TSO

STANDARDS. This is the case with transponders.



In other instances the equipment MUST BE TSO'd. This is the case with IFR

GPS units.



You mentioned, "...manufacturers who have gone to the expense and effort of

obtaining TSO approval for a piece of equipment..."



If simply meeting the TSO requirements is adequate, why should a

manufacturer "go to the expense and effort"?





--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Jan 09, 2007 9:49 am Post subject: GRT GPS TSO

1/9/2007



Hello Bret, Continuing our dialogue.



1) You wrote: "If I get called out on the carpet for a non-TSO'd GPS, what 

would they say

about my non-TSO'd TruTrak AP, Ray Allen trim system, GRT AHRS/Magnetometer,

HID homegrown landing lights, LED nav lights, etc?"



I believe that IFR / Night equipment for ABEA's falls into one of the 

following categories:



1A) Purely optional equipment installed at the desire of the builder with no 

existing regulatory requirement.



1B) Equipment required by FAR 91.205 (b), (c), and (d) because of wording in 

the aircraft's Operating Limitations.



1C) Equipment required by FAR 91.205 (b), (c), and (d) because of wording in 

the aircraft's Operating Limitation that is identified as needing to be 

"approved" in those paragraphs.



1D) Equipment required by other paragraphs within the FAR's that would apply 

to all aircraft, both type certificated with standard airworthiness 

certificates and ABEA's with special airworthiness certificates.



1E) Equipment required by the AIM for certain types of operations that would 

apply to all aircraft, both type certificated with standard airworthiness 

certificates and ABEA's with special airworthiness certificates.



2) Your non-TSO'd TruTrak AP, Ray Allen trim system, GRT AHRS/Magnetometer,

HID homegrown landing lights and other equipment of that ilk would fall into 

category 1A above and should generate no FAA criticism because it is not 

TSO'd.



3) Your LED nav (position) lights would fall into category 1C above. See 

91.205 (c), (2). If your initial ABEA airworthiness inspector issues the 

aircraft a special airworthiness certificate he has, by implication, 

"approved" those position lights in the name of the FAA Administrator (see 

FAR 1.1). If he refuses to issue the certificate and demands to see TSO 

markings because the regulations require it, he is wrong. If he refuses to 

issue the certificate and demands to see either TSO markings or test results 

showing that the lights meet FAR Part 23 position light standards, that is 

within his prerogative as an inspector.



4) If you had only a non TSO'd GPS aboard and performed a specific operation 

that the AIM required a TSO approved GPS for then you would not be in 

compliance with 1E and may be subject to a charge of careless or reckless 

operation (see FAR 91.13).



5) You wrote: "My understanding is that before flight into the national air 

system, under

IFR, the pilot/builder of the OBAM aircraft must determine and document via 

flight testing that the aircraft and it's systems meet the requirements for 

IFR flight, night flight, etc."



This is certainly common sense. I would be interested in seeing some 

regulatory basis for the above. The sources that I am aware of that cover 

specific ABEA requirements for IFR and night flight are the Operating 

Limitations for that aircraft and the references contained therein including 

FAR 91.319.



FAR 91.319 (d), (2) reads "Operate under VFR day only, unless otherwise 

specifically authorized by the Administrator."



The Operating Limitations will contain these words: "After completion of 

Phase I flight testing, unless appropriately equipped for night and/or 

instrument flight in accordance with 91.205, this aircraft is to be operated 

under VFR, day only."



If the aircraft meets the "appropriately equipped" criteria it is considerd 

by the FAA to have been given the Administrator's specific authorization to 

fly at night and under IFR. What we have been discussing is what constitutes 

"appropriately equipped".**



OC -- The best investment we will ever make is in gathering knowledge.



**PS: It is interesting to note that if the aircraft is given authorization 

for aerobatic flight in the Operating Limitations that those maneuvers must 

be specifically tested and documented in the aircraft's logbook.



PPS: You wrote: "This is a really interesting topic and I truly respect your 

opinions.

It is evident you have a good understanding of these issues."



I appreciate your kind words.



---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Jan 09, 2007 10:52 am Post subject: GRT GPS TSO

1/9/2007



Hello Bill,



1) You wrote: " In some instances the regs require that a piece of equipment 

MUST MEET TSO

STANDARDS. This is the case with transponders. In other instances the 

equipment MUST BE TSO'd. This is the case with IFR GPS units."



Both TSO-145A and TSO-C146A dealing with IFR GPS units contain the following 

paragraph (MPS means Minimum Performance Standards):



"g. Deviations. The FAA has provisions for using alternative or equivalent 

means of compliance to the criteria set forth in the MPS of this TSO. 

Applicants invoking these provisions shall demonstrate that an equivalent 

level of safety is maintained and shall apply for a deviation per 14 CFR § 

21.609"



2) TSO-C129a is an older TSO dealing with IFR GPS units and does not contain 

specific alternate compliance words within it as is the case with more 

current FAA TSO's, but here is a quote from the current AIM, note the use of 

the word "equivalent":



"g. Equipment and Database Requirements.



1. Authorization to fly approaches under IFR using GPS avionics systems

requires that:

(a) A pilot use GPS avionics with TSO- C129, or equivalent, authorization in

class A1, B1, B3, C1, or C3; and......"



3) You wrote: "If simply meeting the TSO requirements is adequate, why 

should a

manufacturer "go to the expense and effort"?"



My point exactly. Simply meeting some of the TSO requirements is not 

adequate to fulfill the intent of the FAA TSO requirements.



GRT implies that they are completely fulfilling the FAA TSO intent by 

writing: "The new RAIM-equipped version provides integrity monitoring and 5 

updates per second to meet the requirements of IFR GPS TSO C129 and C146."



The equipment must either be TSO'd in accordance with the provisions of FAR 

Part 21 Subpart O or FAA deviation approval from the TSO in accordance with 

paragraph 21.609 must be obtained. Neither one of these are easy actions to 

take and there is no indication in the GRT statement posted that either 

action has been taken. Hence my suspicion of misleading weasel wording.



OC -- The best investment we will ever make is in gathering knowledge.



Time: 09:35:15 AM PST US

From: "Bill Denton" <bdenton(at)bdenton.com>

Subject: RE: GRT GPS TSO



"A piece of equipment either meets the full TSO requirements and is marked

TSO compliant or it is not TSO'd."



True, but not necessarily the point...



In some instances the regs require that a piece of equipment MUST MEET TSO

STANDARDS. This is the case with transponders.



In other instances the equipment MUST BE TSO'd. This is the case with IFR

GPS units.



You mentioned, "...manufacturers who have gone to the expense and effort of

obtaining TSO approval for a piece of equipment..."



If simply meeting the TSO requirements is adequate, why should a

manufacturer "go to the expense and effort"?

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Tue Jan 09, 2007 2:13 pm Post subject: GRT GPS TSO

1/9/2007



Hello Bret:



1) You wrote: "As you can see, the FAA has left a wide loophole with the 

phrase "or equivalent"."



The FAA has learned from experience that locking technical requirements in 

bureaucratic documents in concrete can come back to bite them when 

technology comes up with a better mouse trap that was not envisioned in the 

document. So now-a-days they caveat their TSO's with a statement to the 

effect that "if you can do it just as good, but maybe a little differently 

we are willing to listen to your proposal."



The process for a request to deviate is described in FAR 21.609 and the 

loophole is not that wide. You might find that entire FAR 21 Subpart O 

interesting reading. You can see that obtaining TSO approval and 

manufacturing in accordance with that approval can be burdensome.**



2) You wrote: "It appears that, from my understanding, a GPS used for IFR 

navigation must meet the minimum standard of RTCA/DO-208 in order to meet 

the standard of TSO-C129 in order to be approved for IFR navigation."



I agree. Also realize that there are other documents referenced in TSO-C129a 

that may contain standards that the unit may have to meet. And the FAA may 

chose to not incorporate all provisions of referenced documents into the 

TSO. Some TSO's are absolutely infuriating -- they say nothing of substance 

technically themselves, but instead reference several documents (such as SAE 

documents) that cost a bunch of money for just three or four pages.



3) You wrote: "Problem is, I don't see where the FAA requires the GPS to be 

"certified".



I agree. The words theFAA uses are "authorization (to perfom IFR operations) 

requires equipment approved IAW TSO -C129" (version C129a is the current 

version). Lawyers may not agree with me, but I bet the Garmin marketing 

people looked at the FAA terminology of "authorization" and "approved" and 

said "certified sounds better to us".



4) You wrote: "I may be confused here but it seems that when Garmin states 

their GNS430 is "IFR Approach Certified", they are only stating that this 

receiver meets the requirements of TSO-C129."



I agree -- and also meeting all the pertinent references to TSO-C129a and 

permitting the FAA oversight of Garmin's production of the GNS 430. (See FAR 

21.615).



In addition now Garmin is stating that the GNS 430W meets all the 

requirements of TSO 146a.



OC -- The best investment we will ever make is in gathering knowledge.



**PS: I worked with Lance Turk, founder of Vision Microsystems, on a special 

size oil temperature probe for my TCM engine. He would not make the probe 

for me because it would be non TSO'd and he did not want to contaminate his 

FAA TSO approved production line. I wound up buying an empty brass 

temperature probe body from Westach and sending it to Lance so that he could 

have one of his technicians epoxy one of the Vision Microsystems special oil 

temperature probe sensors into that brass body's cavity. Works like a charm.



---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

khorton01(at)rogers.com
Guest

Posted: Tue Jan 09, 2007 3:06 pm Post subject: GRT GPS TSO

On 9 Jan 2007, at 17:10, <bakerocb(at)cox.net> wrote:



 	  Quote: 	
		   



 4) You wrote: "I may be confused here but it seems that when Garmin  

 states their GNS430 is "IFR Approach Certified", they are only  

 stating that this receiver meets the requirements of TSO-C129."



 I agree -- and also meeting all the pertinent references to TSO- 

 C129a and permitting the FAA oversight of Garmin's production of  

 the GNS 430. (See FAR 21.615).




	


One more thing -  if Garmin says that their GNS430 is "IFR Approach  

Certified", it also means that it has been found by the FAA to be  

capable of being installed to meet the guidelines in Advisory  

Circular 20-138A Airworthiness Approval of Global Navigation  

Satellite System (GNSS) Equipment.



Kevin Horton         RV-8 (finishing kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum