Service Bulletins 19-08-26 and 16-05-23 Published - Nose gear leg and fork

[MMiller]

Originally Posted by pilotyoung

Will you explain the reason or cause for issuing a Safety Directive vs. a Service Bulletin vs. a Notification or Letter?

John, that?s a great question, there is not a lot of info on this subject out there.

First, the definitions. This is out of AC65.32a. The FAA copied it verbatim from ASTM F2295 7.2.2.1 through 7.2.2.3.

z. Safety Directive ASTM Designation F2483. A directive issued by a manufacturer of a special LSA intended to correct an existing unsafe condition. Compliance with safety directives is addressed in 14 CFR part 91, ? 91.327 and the recording is required in ? 91.417. Safety directives are addressed in applicable consensus standards which include provisions for maintaining the continued airworthiness of an aircraft and correcting safety-of-flight issues. Safety directives are considered mandatory on SLSA.
(1) Safety Alert. For notifications that require immediate action, see ASTM F2295.
(2) Service Bulletin (SB). For notifications that do not require immediate action but do recommend future action, see ASTM F2295.
(3) Notification. For notifications that do not necessarily recommend future action but are primarily for promulgation of continued airworthiness information, see ASTM F2295.


You need a copy of the ASTM standards to understand the mechanics of what determines a Safety Directive. This material is copyrighted so I can?t post a copy or provide a link, but I will try to explain.

ASTM F2295 uses a formula to calculate the ?Safety Risk Factor? by using weighted values (between -1 & +4) to the following;
1) Safety Effect (Catastrophic to Minor)
2) Operational Use (hire or personal)
3) Percent of use by Population (% of fleet for hire)
4) Number of Occurrences
5) Events vs. Population
6) Time between events

The ?Safety Risk Factor? is the product first three lines added to the sum of last three line. It will have a value between 2 and 40.

We plug this into the F2295 Risk Assessment Evaluation Chart. The Y axis is? Safety Effect? (0= minor, 4= Catastrophic,) and the X axis is ?Safety Risk Factor? (0 ? 50.) The chart has 3 diagonal bands, the bottom left band (from 0,0) is ?General Aviation Alert,? The middle band is ?Potential Safety of Flight Bulletin,? and the top right band (to 50,4) is ?Urgent Safety of Flight Situation.?

Simply locate a point on the chart using the ?Safety Effect? value and the calculated ?Safety Risk Factor? and see what band the event falls into.

Some of this may have changed. As of October 3, 2019 the FAA retired F2295 and replace it F3198-18. F2295 only applied to Airplanes and Gliders. Gyros, WS, PP and Balloons each had their own Specification for ?Continued Airworthiness,? each containing unique definitions for ?Safety Alert,? ?Service Bulletin? and ?Notification.? The new specification F3198-18 crosscuts and is common to all Light Sport classes.

[greghughespdx]

Originally Posted by pilotyoung

Greg,

We all appreciate your honesty and detailed explanations on this forum. This thread has raised questions about Safety Directives and Alerts, Service Bulletins, and Notifications and Letters.

Will you explain the reason or cause for issuing a Safety Directive vs. a Service Bulletin vs. a Notification or Letter?

Thanks.

John

MMilller covered the standards pretty well in his reply. The standards he mentioned significantly define the risk assessment process we follow, which is the primary and key component of our decision process. From our web site, in the Service Information section, we classify the different documents we publish (which are listed here in descending order of risk severity/priority) as follows:

SAFETY DIRECTIVES AND ALERTS
For all ELSA or SLSA aircraft, these documents represent critical safety of flight notifications that require immediate action before further flight. Safety Directives and Safety Alerts are mandatory and may be enforced by the FAA. Note that for EAB aircraft, similar-level published information may be included under the ?Service Bulletins? category of documents.

SERVICE BULLETINS
Service Bulletins typically do not mandate immediate action from a regulatory perspective but do strongly recommend future action. Timeframes and methods to comply may vary and are described in each document. These are items that represent an important or critical need and should be reviewed and complied with per the contents of each document in the specified timeframe. Van?s Aircraft strongly encourages all owners and operators to comply with the information in these documents.

NOTIFICATIONS AND LETTERS
Notifications/Letters do not necessarily recommend future action but are primarily for the promulgation of continued airworthiness information. These documents explain or notify owners of service- or configuration-related information pertaining to their aircraft. It is important to review these notifications and letters when they are published.

REVISIONS AND CHANGES
This section includes revisions to Van?s Aircraft documentation, such as Builder Plans/Kit Assembly Instructions and other aircraft documents, and includes explanations of what?s changed in each revision where appropriate. Note that we do not typically post documentation updates that consist of minor changes such as spelling and minor error corrections, etc. Rather, updates are published here when material changes occur.

The risk assessment formula (we are operating under the new 3198-18 standard by the way), which results in the Safety Risk Factor calculation is used to objectively calculate the risk associated with the specific situation being assessed. We can always "bump up" the risk/severity if there is a reason to do so. This provides a standardized method of risk scoring that is generally accepted by the industry and any applicable regulatory agencies, while also allowing us room to act in a more conservative manner than the risk score dictates, if and when we to determine it is necessary to do so.

In addition, a vendor of a component (for example a Rotax engine) may issue a safety directive or service bulletin. We then issue a similar document at or above the level of risk specified by the component vendor, if applicable to our aircraft.

Hope that helps!

greg

[pilotyoung]

Greg and MMiller,

Thanks for your replies. It helps me understand your reasoning for deciding which one to use.

John

[enterprise]

found my answer in engine mounting section. Carry on

[skydiverlv]

I am finished with the nose gear installation and have the 18" bits and guide bushings for sale listed in the classifieds.
Included are the 3 bits, 2 guide bushings and the length of PEX tubing that makes the process much easier.
The bushings and PEX are the same diameter and I found that taping the two end to end with gorilla tape was of much benefit. After taping you can easily insert the guide bushing into the existing 3/8" hole of the mount inside the tunnel then drill through the PEX and bushing.

[DHeal]

A Covid-19 related question: Is compliance with the nose strut /nose gear fork SBs a one-person job? If not, where during the install process are two people needed or beneficial?

[skydiverlv]

I performed the gear leg replacement solo and found no need for another set of hands.

[bajapilot]

Had no problem doing it myself.

[DHeal]

A tip for SB 19-08-026 compliers: I found that an approximately 16" length of 5/16" dia. wooden dowel was very useful in driving out the two lower AN 6 bolts. Any straight metal 5/16" dia rod or tube would do as well.

[DHeal]

Here is another tip for SB 19-08-026 compliers: I took note of some earlier commentors' useful suggestions to use a tube or spring to keep the drill bushing in position while drilling the two lower strut/motor mount holes. I took an @ 14 5/8" long piece of @ 5/16" ID tube (plastic, rubber, or metal) and taped one end of the tube to the appropriate drill bushing. Insert the appropriate drill bit through the tube and bushing, then place a small thrust washer, an @ 1 1/4" long moderate-force compression spring, and then another small thrust washer (add a bit of grease on the washers) at the end of the tube. Tighten this "assemblage" in the drill chuck so that the tip of the drill bit falls just shy of end of the bushing (think "frightened turtle"). It is then a very easy job to sit in the cockpit, index the bushing into the existing 3/8' firewall hole, line up the drill, hold the tube to keep it from spinning, and push the drill motor to drill the holes -- the "assemblage" places pressure on the bushing and helps to keep it properly aligned while the drill bit does it's work (don't forget to use some drill bit lubricant such as Boelube, etc.). Easy-peasy!