Safety Recommendation A-10-061
Details
Synopsis: During recent investigative testing, the National Transportation Safety Board (NTSB) learned that a failure within a helicopter’s radio altimeter system could prevent the look-ahead feature of a Honeywell MK XXII Enhanced Ground Proximity Warning System (EGPWS) from functioning during flight and that the pilot would possibly be unaware that this feature within the system is not operational. The look-ahead feature provides visual and aural terrain avoidance alerts by comparing the aircraft’s projected flightpath to a database containing terrain and obstacle information. The absence of these alerts, when the pilot does not know the alerts are not functioning, could mislead the pilot thereby significantly reducing the safety of flight.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Once Honeywell revises the MK XXII Enhanced Ground Proximity Warning System (EGPWS) software logic (as described in Safety Recommendation A-10-60), require all operators using the Honeywell MK XXII EGPWS to install the revised software.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Unacceptable Action
Mode: Aviation
Location: Washington, DC, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: 80709
Accident Reports:
Report #: None
Accident Date: 4/14/2010
Issue Date: 4/14/2010
Date Closed: 7/8/2013
Addressee(s) and Addressee Status: FAA (Closed - Unacceptable Action)
Keyword(s): Collision Avoidance

Safety Recommendation History
From: NTSB
To: FAA
Date: 7/8/2013
Response: We do not agree that the FAA’s decision not to require operators to install the free software that corrects the problem with the Honeywell MK XXII EGPWS “reflects the best interests of aviation safety.” We continue to be concerned that, when the FAA implements a requirement for a helicopter terrain awareness system (HTAWS), a Honeywell MK XXII EGPWS for which the defective software logic has not been corrected will nevertheless satisfy the FAA’s new requirement for an HTAWS. However, because the FAA has made it clear that it considers its actions in response to this recommendation to be complete and it will take no further action, Safety Recommendation A-10-61 is classified CLOSED—UNACCEPTABLE ACTION.

From: FAA
To: NTSB
Date: 4/8/2013
Response: -From Michael P. Huerta, Administrator: In its letter dated March 6, 2012, the Board asked the Federal Aviation Administration to explain how it will ensure that any Honeywell MK XXII EGPWS used to satisfy a requirement for a terrain awareness system in helicopters (HTAWS) has been revised. In that letter, the Board expressed concern that when HTAWS becomes required equipment under proposed section 135.106 (for Helicopter Emergency Medical Services (HEMS)), an unmodified EGPWS may be considered compliant. The Board also expressed concern that Special Airworthiness Information Bulletin (SAIB) SW-II -31 is advisory only and would not require operators to incorporate the software upgrade. In our initial response, we stated that if we issued an airworthiness directive when the installation of HTAWS is not required, some operators may elect to disconnect the HTA WS to allow for dispatch. We maintain that having the HTAWS operational in a potentially degraded mode provides a higher level of safety than operating without HTAWS. Assuming the HEMS final rule does not change from the proposed rule, helicopters would not be required to be equipped with HTA WS for 3 years. Currently, Honeywell is actively working to raise operator awareness regarding the deficiency as well as the availability of the software update to resolve the issue. Specifically, Honeywell has posted SAIB SW -11 -31 and associated Honeywell Service Bulletins on their EGPWS Web site and is offering this update at no cost to operators. Furthermore, correspondence with Honeywell indicates that operators are actively incorporating these updates into their equipment. Additionally, we believe a pilot should never depend only on a terrain warning system to avoid terrain or obstacles. We carefully reconsidered our actions, and we continue to find that our response to this safety recommendation reflects the best interests of aviation safety. Accordingly, we plan no further action in direct response to this safety recommendation.

From: NTSB
To: FAA
Date: 3/6/2012
Response: In our January 11, 2011, letter to the FAA about this recommendation, we acknowledged the FAA’s concern that, because the installation of a terrain awareness system in helicopters (HTAWS) is not yet required, were the FAA to issue an airworthiness directive, it is likely that some operators would disconnect the HTAWS to allow dispatch. The FAA believed that having the system operating in a degraded mode is safer than operating without HTAWS. On May 11, 2011, the FAA issued Special Airworthiness Information Bulletin (SAIB) No. SW 11 31, which was subsequently revised on July 18, 2011. The SAIB strongly recommends that owners and operators of Honeywell MK XXII EGPWS update their systems with the revision developed in response to Safety Recommendation A-10-60. The FAA indicated in 2009 that it was developing a notice of proposed rulemaking (NPRM) to address Safety Recommendations A-06-15 and A-06-19 (which recommend that TAWS be required on rotorcraft). On October 12, 2010, the FAA issued an NPRM, titled “14 CFR Parts 1, 91, 120, and 135 Air Ambulance and Commercial Helicopter Operations, Part 91 Helicopter Operations, and Part 135 Aircraft Operations; Safety Initiatives and Miscellaneous Amendments; Proposed Rule.” This NPRM proposes to require that helicopters used for emergency medical service (HEMS) operations be equipped with HTAWS. In our January 11, 2011 letter, we indicated that issuance of an SAIB advising of the availability of the Honeywell revision was an appropriate first step. However, an SAIB is advisory only and does not constitute a requirement. We are concerned that after the HTAWS requirement for HEMS is implemented, a Honeywell MK XXII EGPWS that has not been modified may still be considered compliant with the HTAWS requirement. The cost of the modification is negligible because Honeywell has made the revision available at no cost, and the revision may be incorporated with nothing more than a simple software upgrade. Without Honeywell’s revisions, situations may arise in which the Honeywell MK XXII EGPWS does not provide needed alerts, but the pilot will not know the alerts are not functioning. Such a situation could mislead the pilot, thereby significantly reducing the safety of flight. It is not acceptable to permit a piece of equipment with a known deficiency to be used to satisfy a requirement for HTAWS in HEMS operations, particularly when the needed revision is available without cost. We ask that the FAA explain, before its action to address this recommendation is complete, how it will ensure that any Honeywell MK XXII EGPWS used to satisfy a requirement for an HTAWS has been revised as recommended in Safety Recommendation A-10-61. Pending our receipt of an acceptable answer to this question, Safety Recommendation A-10-61 remains classified OPEN—ACCEPTABLE ALTERNATE RESPONSE.

From: FAA
To: NTSB
Date: 11/22/2011
Response: -From J. Randolph Babbitt, Administrator: The Federal Aviation Administration (FAA) has issued Special Airworthiness Information Bulletin (SAIB) No. SW-1l-31, dated May 11, 2011 (enclosure). The SAIB strongly recommends that owners and operators of rotorcraft equipped with a Honeywell MK XXII EGPWS that has not been updated correct a condition where there could be unannunciated loss of functions of that system. The SAIB strongly recommends that owners and operators contact Honeywell to make arrangements to install and incorporate the part number 965-1595-028 Application Software Version as described in Honeywell Service Bulletin ATA Number 965-1595-34-22. The SAIB warns that failure to do so could result in less than desired or expected protection from inadvertent controlled flight into terrain or obstacles. Installation of a terrain awareness system in helicopters remains advisory in nature and we maintain that the safety impact does not warrant issuance of an airworthiness directive. Nevertheless, Honeywell reports good response from customers, even though it does not know what percentage of equipped aircraft have been modified. I believe that the FAA has effectively addressed these recommendations, and I consider our actions complete.

From: NTSB
To: FAA
Date: 1/11/2011
Response: The NTSB acknowledges the FAA’s concern that, because the installation of a terrain awareness system in helicopters (HTAWS) is not yet required, were the FAA to issue an airworthiness directive, it is likely that some operators would disconnect the HTAWS to allow dispatch. The FAA believes that having the system operating in a degraded mode is safer than that alternative; therefore, the FAA plans to issue a special airworthiness information bulletin (SAIB) to alert owners and operators about the problem discussed in these recommendations and to advise operators of Honeywell’s scheduled software upgrade. The FAA further indicated that, after Honeywell makes the software upgrade available, the SAIB will be revised to alert owners and operators. The NTSB points out that we have not recommended that the software revision be required until after it is developed and available in response to Safety Recommendation A 10 60. The NTSB also points out that, although HTAWS is not yet required, in response to Safety Recommendations A-06-15 and A-06-19 (which recommend that TAWS be required on rotorcraft), the FAA indicated in 2009 that it was developing a notice of proposed rulemaking (NPRM) to address these recommendations. It is likely, however, that the software revision will be available before the NPRM and final rule requiring HTAWS are implemented. Issuance of the SAIB, which is advisory only and does not constitute a requirement, is an appropriate first step; however, before the FAA’s actions in response to this recommendation are complete, it will need to confirm that operators using the Honeywell EGPWS have downloaded and installed the free software upgrade. This may be done through a requirement or via information that Honeywell may provide to the FAA demonstrating that the software revision has been downloaded by all operators. Accordingly, pending the FAA’s confirmation that all operators using the Honeywell MK XXII EGPWS have installed the free software revision, Safety Recommendation A-10-61 is classified OPEN -- ACCEPTABLE ALTERNATE RESPONSE.

From: FAA
To: NTSB
Date: 6/29/2010
Response: MC# 2100239 - From J. Randolph Babbitt, Administrator: Helicopter TAWS (HTAWS) is a safety advisory system; it is not a required system in any rotorcraft. If we issue an airworthiness directive, it is likely a number of operators will simply disconnect the TAWS system to allow dispatch. Because the failure only inhibits an alert, as opposed to providing false information, we believe having the system on board and working in a degraded mode is safer than not having the system operational during the interim period until the software fix becomes available. We plan to issue a Special Airworthiness Information Bulletin (SAIB) to alert owners and operators about the problem, and Honeywell's scheduled software upgrade. When Honeywell makes the software upgrade available, we will revise the SAIB to communicate this information to owners and operators. I will keep the Board informed of the FAA's progress on these safety recommendations, and provide an updated response by July 2011.