What’s Up with FAA AD on Superior Air Parts ?

engine and crankshaft
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Superior Air Parts’ Response to the NPRM Issued by FAA Regarding Certain Crankshafts in Lycoming-360 style Reciprocating Engines

 Failures in 2017 (2) and 2018

FAA told Superior 2 weeks before AD

Odd gestation period for potential problem for 115 aircraft!!!


Representatives of Superior Air Parts, Inc., announced today that the company is aware of the FAA’s recent notice of proposed rulemaking (NRPM) concerning a proposed airworthiness directive (AD) for Superior Air Parts (SAP) model O-360, IO-360 reciprocating engines, and certain Lycoming Engines model AEIO-360, IO-360, and O-360-series reciprocating engines.

SAP Scott Hayes

Unfortunately, we were only informed of the proposed rule two-weeks ago. Since then, we have been in contact with the FAA regarding their findings to fully understand the issue and identify the most likely cause of the failures,” stated Scott Hayes, VP of sales and marketing Superior Air Parts, Inc. “Our engineering team is currently reviewing all of the available information, and once we have determined the actual cause, we can work with the FAA to determine the most logical course of action.”

Hayes said that the FAA estimates the AD would affect 115 crankshaft assemblies installed in U.S. registered certified aircraft.

“All I can say for certain is that it is still just too early to form any type of conclusion about what caused these three crankshafts to fail the way they did,” stated Bill Ross, VP of product sBill Ross SAPupport, Superior Air Parts, Inc. “We want every one of our customers to know that we put safety ahead of everything and will do everything in our power to find the root cause as soon as possible.”


SAP headquarters, Coppell, TX


Reading between the lines of the SAP statement (“we were only informed of the proposed rule two-weeks ago”) flags that something may be amiss in this NPRM / AD notice.  

  • Over the past 58 days of 2020, the FAA has issued 48 such documents. One can conclude that the professional staff has been grinding to issue these time-sensitive, safety critical documents.
  • This same cadre of FAA airworthiness experts has been subject to public criticism for the slow issuance of ADs for the Boeing 737 Max 8 in particular comments from the Chair of the House T&I Committee.

Chairman DeFazio







So, what are the salient points of the FAA’s notice?




  • “The FAA learned of three SAP crankshaft assembly failures that took place on March 6, 2017, August 3, 2017, and October 31, 2018, that resulted in the loss of engine power and immediate or emergency landings. Since the FAA received these reports, the FAA determined that the crankshaft assembly failures resulted from the manufacturing process at SAP’s crankshaft vendor during 2012 and 2014.”
    • ASSUMPTION: one would assume that the pilots of these three aircraft reported ASAP the crankshaft failure to SAP (“send me a replacement and pay for the repair”?)
    • ASSUMPTION: assume also that pilot informed the local FAA office and the OEM alerted Engine Certification Directorate/ local MIDO about this failure
    • COMMENT: Both SAP and the FAA has been aware of this crankshaft problem as early as almost 3 years ago and with some level of heightened risk 16 months ago!!!
  • “The FAA’s analysis concluded that all three SAP crankshaft assembly failures were the result of this fatigue cracking. This condition, if not addressed, could result failure of the engine, in-flight shutdown, and loss of the airplane.”
  • The FAA estimates that this proposed AD would affect 115 crankshaft assemblies installed on airplanes of U.S. registry. This cost estimate does not include 77 SAP crankshafts installed on experimental engines since these engines are not included in the applicability of this AD. Compliance cost per crankshaft assembly is identified below.

Labor cost = 61 hours per crankshaft assembly replacement × $85 Hourly Wage = $5,185.

Equipment costs per crankshaft assembly replacement = $9,636 (Source: Average of the two manufacturers).

$5,185 labor per crankshaft assembly + $9,636 equipment costs per crankshaft assembly replacement = $14,821 compliance cost per engine.

The total costs to U.S. operators is $1,704,415, or $119,309 in annualized costs. There are no additional costs after removing and replacing the crankshaft assembly.

  • COMMENT: Replacement is cheaper than repair; so, it would appear that under a cost/benefit microscope it would appear safety and economic impact merit not waiting the time which the FAA used for gestating this AD.
  • COMMENT: 115 aircraft is a substantial number which should support faster action.

Lycoming O-360 engine


  • FAA ordering paragraphs:

(e) Unsafe Condition

This AD was prompted by three crankshaft assembly failures that resulted in the loss of engine power and immediate or emergency landings. The FAA is issuing this AD to prevent failure of the crankshaft assembly. The unsafe condition, if not addressed, could result in failure of the engine, in-flight shutdown, and loss of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Action

Within 25 engine operating hours after the effective date of this AD, remove the crankshaft assembly from service.

  • COMMENT: Given these justifications for the crankshaft removal, how does the FAA explain this more-than-a-year gestation?


  • According to SAP, the FAA contacted SAP two weeks ago. If this problem merits THE EXPEDITED ACTION proposed in the AD, contacting the OEM much earlier seems appropriate.
  • If the assumption that the pilots contacted SAP soon after the crankshaft failure is correct, why didn’t the company get involved in the FAA process MONTHS AGO?


Whatever the reasons for these incongruous delays, aviation safety will be improved by this action NOW!!!

airplanes at risk


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