Mr. Stenevik, 

Attached are the ELoS questions for the B-24. I can be reached at (301) 219 5476 or I'll try to call you as 

well. Like the questions concerning the B-29, this set will be posted in regulations.gov.

Thanks

Miguel Vasconcelos

AFS-830

Record of Telephone & E-mail Communication

October 7, 2014

Docket No. FAA-2014-0482

CAF Petition for Exemption From 91.319(c) of Title 14, Code of Federal Regulations

Exemption No. 10853

ELoS Questions (Consolidated LB-30/B-24A, N24927)

1. What are the risk factors and safety issues in the LB-30/B-24A that create hazardous conditions 

which could impact people and property being overflown which would not be found by the operation of 

a similar civil type, i.e. Boeing 307/C-54/Limited B-17?

2. What safety data do you have concerning the aircraft while in service such as accident rate and 

types and classification of accidents/incidents? For example, the accident rate in non-combat operations 

(all B-24 versions and variants) ranged from 40 to 96 per 100,000 hours, while 300 were lost in accidents 

in 1943 and an accident fleet attrition rate of 30% (5,500 out of over 18,000 produced). The causes and 

contributing factors are relevant to any ELoS determination. In other words, what failed and what is 

likely to fail, and how, and what is being done to mitigate these. For example, in general terms, how are 

the following B-24 safety issues addressed or mitigated by the CAF in operating N24927? Note: Some of 

the questions below may lead to or provide an answer.

 Advanced airfoil (Davis wing) and high wing loading;

 Troublesome fuel transfer system and fire potential;

 Poor-engine out performance;

 Landing gear weaknesses and hydraulic failures;

 Structural weak areas affecting crash-landing survivability;

 Tail buffeting/flutter;

 Flight stability and loss of control in some configurations/weights or in turbulence.

3. How have you incorporated the applicable Army Air Corps/Force Regulations and SOPs 

(operational) applicable to the LB-30/B-24A to CAF’s operations of N24927? Any RAF guidance?

4. What is the technical substantiation for the modifications to the R-1830-94 instead of S3C4G, -33, -

67 engines installed in the aircraft (Possibly -65s as well with Stromberg PB12 Carbs.)? Please submit a 

copy of these materials (e.g., reliability analysis, proving & validation test data). Are the most current R1830-94 Service Instructions being used? Does the CAF uses a QEC unit as an option in addressing engine 

changes and /or malfunctions?
5. With the understanding that the LB-30 and early B-24s, what technical data validates the 

combination of the Hamilton-Standard Hydromatic propellers (both narrow and wide (paddle) types) 

and the -94 R-1830? Is it a sanctioned combination? Any civil equivalent? 

6. Are the turbo/superchargers (GE B-22 type?) installed and functional? If so, what measures have 

been taken to mitigate the hazards these may introduce to the operation of the aircraft? If functional, 

what measures are used to mitigate the defects in the buckets?

7. What is the modification status of the aircraft with respect to the TCDS No. LTC-6, Rev. No. 3, 

Consolidated Vultee Aircraft Corporation, LB-30 (Army) dated February 21, 1947? How far from 

conformity with LTC-6 is the aircraft? Please submit relevant records especially since the conversion 

back to B-24A begun in 2006-08.

8. Have the Notes 1 through 5 in LTC-6 been complied with? If not, why and what mitigating strategies 

have been implemented in lieu of? 

9. Since over time Consolidated improved upon many of the deficiencies of the early B-24s (LB-30/RAF 

Liberator I & II, B-24A-D) as it developed later versions (e.g., J and H), what risks may have been reintroduced by the CAF into N24927 by converting it back to a stock “A” model? If so, how are they 

mitigated?

10. What is being done to prevent a recurrence of the May 26, 2012 nose gear collapse, especially in 

light of the fact that this failure was common in early LB-30/B-24s? What has been done to prevent a 

recurrence of the landing gear failure event which took place on September 16, 1996, in which a main 

landing gear brace failed?

11. What has been done to eliminate the risk of fuel leaks in the fuselage/bomb bay areas? Does the 

aircraft have an early fuel transfer system (limited cross-feed capability) or the systems installed in later 

models? Has the fuel transfer system been modified or made inoperative? If so, how? Are potential 

ignition sources (e.g., hydraulic/electric motors) understood and mitigated, e.g., ventilation without the 

benefit of using the bomb bay? Provide technical data on any such modifications or actions.

12. What has been done to eliminate the risk of fuel leaks in the wings (including routing inward back 

into the fuselage areas)? Has the fuel tank system been modified? If so, how? Are the Aux tanks aft of 

the No. 1 and No. 4 engines installed and functional? Provide technical data on any such modification or 

action. Also, what actions have been taken to minimize fuel leaks related to the priming system? 

13. What are all of the applicable USAAC/USAAF T.Os for the aircraft in effect at the time of retirement? 

Can you provide a listing and data showing that all applicable T.Os and TCTOs (to end of operational 

service - 1947) have been complied with?

14. What are the differences between the current AIP and the military technical guidance, especially in 

terms of inspection schedules and replacement times (life-limits)? Does the AIP contain progressive 

schedules” Which inspection process is used, e.g., just annual/100 hours, 4 x 25 hours inspection 

covering each engine and a few major components (right wing with No. 1 engine) at a time, IRAN, or 

overhaul as in C & D check-like? Any leftover processes (non USAAF) from its time under Mexican 

Registry?

15. Has AD 2003-18-01 Airworthiness Directives; General Dynamics (Convair) Model P4Y-2 Airplanes, 

General Dynamics (Consolidated-Vultee) (Army) Model LB-30 Airplanes, and General Dynamics 

(Consolidated) (Army) Model C-87A Airplanes, as amended, been complied with? 

16. What other ADs, SBS, or other civil requirement/guidance applicable to the LB-30/B-24A have been 

considered and incorporated? 

17. What ADs, SBS, or other civil requirement/guidance applicable to the R-1830, the HamiltonStandard propellers or other appliances installed in N24927 have been considered and incorporated? 

For example, has AD 81-13-06 Rev. 2 (repetitive, and using Hamilton Standard Manual No. 130B) been 

complied with?
18. What flight emergencies, in-flight failures, in-flight engine shutdown and post-flight discrepancies 

have occurred since 2006? What has been done to prevent a recurrence? 

19. Is the fire detection and suppression system functional and properly inspected?

20. What is the SOAP (Spectrometric Oil Analysis Program) frequency and results since September 

2010?

21. What are the details of the aging aircraft and corrosion control programs?

22. Has the front wing spar splice in N24927 been modified in a manner similar to the modifications 

made to N224J under Report No. CF-B4J-44052-001SA? If so, is there adequate technical justification for 

such a major modification to the aircraft?

23. What are the configurations and redundancies installed in the aircraft? What non-standard 

additions were incorporated that enhance safety?

24. The B-24 has a poor history of survivability during ditching/crash landing. What precautions have 

been taken to maximize survival in case of ditching or crash landing? , such as adequate passenger 

locations, removable stiffeners to brace lower structure/bomb bay, structural reinforcements to 

mitigate fuselage compression failures immediately behind the cockpit, and ditching/crash landing 

belts/restraint canvas?

25. Have there been any instances of tail vibration, flight control deformation, or flight control cable 

failures? Does the CAF restrict N24927’s maximum speed for any structural concern? For example, the 

H model’s speed was reduced to 300 mph to reduce the possibility of in-flight structural failure of flight 

controls. Note: For safety reasons, in operating its B-24J, The Collings Foundation has reduced Vne to 

200 mph.

26. Is the CG range maintained in a conservative range with respect to 23 percent MAC to 32 percent 

MAC (narrow CG range)? The purpose is to ensure that at all times, any of the aircraft’s flight stability 

issues (longitudinal) due to CG location is safely maintained. This is an issue with the “short-nosed” B24s, and in fact the nose extension in later models was primarily to help, but not resolve, this CG issue.

27. The expectation is that the most experienced LB-30/B-24 crew would be used. As such, can you 

Please provide the qualifications and experienced of the proposed flight crew for the flight – PIC, SIC, 

and FE? Include Total Time, Time in Type, ratings, currency and recency.

28. Please provide information showing that the FE assigned to the LB-30/B-24A (a required crew 

position) is properly qualified, e.g., experience A&P and training as a crewman? Has USAAC/USAAF B-24 

FE training been adhered to or considered?

29. What ground crew and grounds support is used? What special pre-flight and post-flight inspections 

can be performed to enhance safety?

30. What QC processes are used in addressing supplier and parts acquisition and use?

31. Has the CAF implemented SMS/CRM/MRM/ORM? If so, please how such does it impact the 

operation of N24927.

32. On the issue of engine/powerplant and propeller failure and related issues, please provide the 

mitigating strategies for the following: 

 Engine Failure & Fire;

 Putt-Putt Fire & Containment;

 Propeller Overspeed and Separation;

 Hydraulic & Electrical Failures;

 MEL & Flight Abort Criteria;

33. What coordination has been done with other Military/Federal entities concerning the proposed 

overflight? Please provide details.

34. For flight over populated areas (maximum avoidance), please discuss and provide detail on the 

following:
 Departure airport, e.g. Manassas;

 Egress/Ingress (Airports & Areas);

 Ground References & Landmarks;

 Formation, Mixed Formation, and In-Trail;

 Lateral Separation & Maneuvering Room;

 Straight & Level, Minimum Maneuvering;

 Nav and Communications;

 Rehearsal, if a special event is Involved;

 In-Flight Divert Procedures Including Divert Airports (e.g. runway 19 at KDCA, Andrews 

AFB) and Crash/Ditching Areas (e.g. Potomac River); 

 Performance, e.g., (1) minimum airspeed for which it is still possible to climb away, 

without change of configuration, if any one engine fails, (2) symmetrical thrust should 

be maintained at all times, and power changes minimized, (3) glide ratio.

 Conservative Performance: Please discuss reduced operating weights, power settings, 

minimum/maximum altitudes, and maneuverability restrictions. Note: For example, 

and for safety reasons, in operating its B-24J, The Collings Foundation has reduced max 

gross weight to 40,000 lb., 2,700 rpm (T.O.) and 2,000 rpm (Cruise), and max bank of 

30o.