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FAA ground Citations with active winglets

37 Posts

24-May-19 11:05

I wonder if this is yet another fallout from the B737 trim business… a large-scale re-examination of systems which have a software component which has no obvious override and which can kill somebody.

Administrator

Shoreham EGKA, United Kingdom

24-May-19 13:24

I’m thinking of one of our member that have installed the active winglets in it’s CJ…
Hope they will find a solution quickly !

LFPT Pontoise, LFPB

24-May-19 14:10

The FAA found the company’s response to reported malfunctions, including service information provided to owners, to be inadequate and unsafe, and ordered the aircraft grounded immediately.

The Federal Register notice was circulated online in advance and specifically rejects the company’s approach to addressing multiple loss-of-control events associated with the malfunctioning system. There is evidence, including Aviation Safety Reporting System (ASRS) reports and an ongoing NTSB investigation, that malfunctions leading to uncommanded maneuvers that risk loss of control have happened half a dozen times or more within an installed fleet of fewer than 100 aircraft modified since the supplemental type certificate was first granted in December 2016.
In the notice, the FAA specifically rejected the company’s proposed service information to disable the system—to use “speed tape” around each Tamarack active camber surface (TACS) to keep them faired in the neutral position during flight. The direct to final rule noted that any modifications mandated through AD action become changes to the type design and that the FAA would need to ensure that the use of speed tape complies with the applicable airworthiness regulations. The FAA determined that the speed tape does not have sufficient testing and analysis to support the type design change.

The FAA action follows an emergency AD issued April 19 by the European Union Aviation Safety Agency (EASA) requiring installed ATLAS systems to be deactivated, with the control surface fixed in place, along with imposition of operational limitations and a requirement for repetitive pre-flight inspections. The EASA directive cited multiple reports of “upset events where, in some cases, the pilots had difficulty to recover the aeroplane to safe flight.”

AOPA is examining the events and process that led to the EASA emergency AD and why it took the FAA five weeks to follow suit. Additionally, the association is reviewing the manufacturer’s subsequent actions, including existing and revised service bulletins, intended to mitigate the risk.

The FAA AD cited the EASA directive and additional information, including that the NTSB investigation of a fatal crash involving an ATLAS-equipped Cessna Citation in November “focuses on the role the ATLAS may have played in the accident. In addition to the accident, five incidents of aircraft uncommanded roll events with the ATLAS activated have been reported to EASA and the FAA. In each incident, the pilot was able to recover from the event and land the aircraft.”

A preliminary NTSB report on the Nov. 30 crash states that a Cessna 525A Citation was climbing through 6,000 feet when it “began a left turn, descended, and disappeared from radar.” The pilot and two passengers were killed in that accident; there were no survivors.

The FAA order grounds all ATLAS-equipped Cessna Citations “until a modification method is developed and approved,” allowing only a limited exception: up to 10 hours of flight under a ferry permit, with limitations on speed and altitude specific to the three Citations models for which ATLAS was approved and installed, and excluding carriage of passengers.

The FAA determined that the manufacturer’s service bulletin is not adequate to disable the system and address the safety risk:

“The FAA finds the service information from the STC holder (Cranfield Aerospace Solutions) does not contain adequate instructions to safely disable the ATLAS. Those instructions include the use of ‘speed tape’ around each Tamarack active camber surface (TACS) to keep them faired in the neutral position during flight,” the FAA emergency AD states. “The FAA would need to ensure that the use of speed tape complies with the applicable airworthiness regulations for use on a movable surface to hold that surface in a fixed position. The speed tape does not have sufficient testing and analysis to support the type design change. This program would involve testing for environmental effects, fatigue analysis, and analysis of hazards due to potential failures of the tape. Without more analysis, the security of the speed tape method to prevent movement of the TACS cannot be assured, and loss of control of the airplane may occur with the ATLAS disabled.”

The FAA estimated that the emergency AD applies to 76 aircraft in the U.S. registry; a company official told AOPA May 7 that ATLAS systems have been installed on 95 aircraft worldwide to date, and all but a few have been modified under the STC as amended in March.

“This AD prohibits flight until the incorporation of an FAA-approved modification. At this time, a modification does not exist; therefore, we have no data to use for estimating the cost of the modification,” the FAA wrote.

Clever idea

I guess the word “disruptive” is currently fashionable:

Administrator

Shoreham EGKA, United Kingdom

25-May-19 09:44

@jasonc
Hope this gets resolved soon!

always learning

LO__, Austria

25-May-19 11:34

Does JasonC have this on his CJ3?

KEMT

25-May-19 14:12

Yes. There is much more to this story. It was triggered by a European pilot flying out of Bournemouth. The following response from Tamarack explains it more.

As we have previously indicated in our forum posts and customer communications, the FAA has issued a corresponding AD to the one issued by EASA, as required by their regulatory harmonization agreement.

The AD can be viewed at this link:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/AOCADSearch/B7A18237C6F54A3986258404004071BA?OpenDocument

What does the AD mean?
The AD prohibits further flight until the AD is resolved. Page 6 of the AD outlines the actions required to placard the aircraft and place the AD in the Airplane Flight Manual.

What is Tamarack doing to resolve the AD?
For over a month now, Tamarack has been working diligently with both EASA and the FAA to provide extensive evidence that the unsafe condition posed by the TCU fastener migration issue was solved with a mandatory service bulletin which we issued in March 2018.

Additionally, earlier this year, we certified TACS trailing edge centering strips which will prevent full deflection of the TACS in the event of a TCU failure, as a ‘belt and suspenders’ approach to system safety.

The FAA AD issued today specifically provides for relief from the AD by demonstrating an ‘Alternate Means of Compliance”. Essentially, an approved AMOC is the resolution to the AD and restores normal aircraft operations until the AD is revised.

Yesterday, the FAA agreed to Tamarack’s proposed AMOC as the mechanism for AD compliance, and it is now at the New York Aircraft Certification Office for approval. The AMOC uses Tamarack engineering and flight test data to prove that compliance with the TCU and Centering Strips service bulletins removes the potential for the unsafe condition listed in the AD. This approval is independent of EASA providing a resolution to their AD.

The vast majority of the fleet is now compliant with the SBs and should allow a return to service once the AMOC is approved by the FAA.

No action is required on your part at this time other than ensuring that your aircraft has complied with all Tamarack SB’s. We are reaching out to the few customers who have not yet complied and will not be relieved from the AD by the AMOC approval.

What is the timing of the FAA and EASA AD resolutions?
We do not have a sense of how long the FAA ACO approval of the AMOC will take, but they have the document and supporting white papers. We have been assured that it is being prioritized by the NY ACO.

We have provided both EASA and the FAA with the same supporting documents. We do not yet have a timeframe for EASA’s independent issuance of a revised AD that provides a similar method of compliance.

What can I do?
Have your maintenance facility ensure that your aircraft is fully compliant with all Tamarack service bulletins and comply with the AD placarding.

If the aircraft needs to be relocated for maintenance, a Special Flight Permit can be issued for up to 10 hours of ferry flight, subject to the operating limitations in the AD.

Tamarack has prepared a Special Flight Permit template which you can use. It will be hosted in the support section of our website or emailed upon request.

The FAA AD also allows customers and interested parties to comment on the document. We would encourage you to do so at: https://www.regulations.gov/docket?D=FAA-2019-0350

What has Tamarack learned about the reason for the AD being issued?

EASA issued the E-AD based on a pilot report of an incident where the pilot reported that the aircraft rolled to “90 degrees in one second”. The AHRS flight data recovered by the AAIB was sent to EASA, the NTSB and the FAA many weeks ago.

The AHRS flight data taken from the incident aircraft by the UK Air Accidents Investigation Branch (AAIB) does not match the pilot report, and reflects a long period event, rather than a sudden one. This data also matches the extensive EASA flight test data, and shows an easily recoverable scenario. The extreme roll rate reported by the pilot was never attained in any of the extensive certification flight testing. It is not possible for the aircraft referenced in the incident to roll at 90 degrees per second.

The pilot did not follow the recovery procedures as described in the Tamarack provided AFMS but still rolled the aircraft level and landed normally.

The incident aircraft had not complied with the ‘no-charge’ mandatory SB we published in April 2018, 51 weeks prior to the incident.

The operator of the incident aircraft had the ‘no-charge’ optional SB for the TACS centering strips in his possession but had not had them installed.

The TCU on the incident aircraft was examined, and the same fastener which prompted the mandatory SB was found to have migrated and caused the TCU failure.

Tamarack already has approved and made available what we believe to be mitigating compliance methods available with our SBs.

Subsequently, there has never been a reported fault on any aircraft in compliance with the TCU fastener SB.

The Indiana accident aircraft referenced in the FAA AD had completed the service bulletin to correct the condition, as has the vast majority of the fleet.

The NTSB has never asked Tamarack to join the investigation. We have offered support and repeatedly inquired, but over the course of 6 months the NTSB has stated that our input is not needed.

We regret the disruption that this AD is causing our valued customers but we continue to work continuously with regulators and industry advocate groups to provide a resolution.

We appreciate your continued support and will keep you updated as we learn more. Please don’t hesitate to contact us with any questions or concerns.

The Tamarack Team

Last Edited by JasonC at 25 May 14:13

EGTK Oxford

25-May-19 21:59

Peter wrote:

I wonder if this is yet another fallout from the B737 trim business…

I doubt the comparison is valid, it seems the active winglet don’t interact with any flight control, especially down/up pitch….

Total malfunctions can lead to increase in fuel/reduced range (+10%?) where an asymmetric malfunction once settled should be similar to asymmetric flaps, slats, airbreaks? (asymmetric engines? fuel tank?) and can be dealt with in similar fashion as getting your foot stuck in the rudder

I think as they sit far on the wings it make them prone to “roll stability issues” (as you need ailerons+speed to counter them but speed may increases their asymmetry, so a pilot may need to be quick with ailerons and moderate with speed) but how that is different from LoC from a sudden gust/turbulence on one wing at slow speeds?

Paris/Essex, France/UK, United Kingdom

25-May-19 22:05

Angie‘s plane did some funny roll stuff, w/o active winglets, but in contrary with some „active“ flight controls. Global5000 that nearly crashed. Ibra wrote:

I doubt the comparison is valid

Looks like the manufacturer designed/integrated features are what’s really to watch out for.

always learning

LO__, Austria

26-May-19 09:34

Yes it is a new thing that one need to watch out for especially as they work in the background (probably they are not even in checklist while flying?) but I just don’t see how that is different to a locked surfaces on one wing for an attentive pilot (if you are an AP guy you may need pax to tell you that wing surfaces are mulfunctioning, sometimes to tell you that engines are on fire or no longer there :) )

Last Edited by Ibra at 26 May 09:35

Paris/Essex, France/UK, United Kingdom

26-Jun-19 21:49

Tamarack reported as having gone bust

Sandpoint, Idaho-based Tamarack Aerospace announced June 7 that it voluntarily filed for Chapter 11 bankruptcy protection earlier in the month, a decision the company termed “a direct result” of recent Airworthiness Directives from the FAA and European Union Aviation Safety Agency (EASA) that have “effectively grounded” Cessna CitationJets, CJ1s, CJ2s, and CJ3s equipped with its active load-alleviation system (Atlas) winglets.

Where does that leave existing installations?

Administrator

Shoreham EGKA, United Kingdom

37 Posts

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