Exemption Request FAR 91.319(c)

Commemorative Air Force

Aircraft: B-24/RLB30 N24927

Request: Exemption from FAR 91.319(c) and associated conditions in the aircraft 

operating limitations

1. Reason for Exemption:

The Commemorative Air Force is requesting this exemption to provide operational 

relief from the restrictions of operating over Densely Populated Areas for our B-24 

Liberator N529B. This request is to allow participation in the flyover of the National 

Mall celebrating the 70th anniversary of the end of WW II, on 8 May, 2015. The 

concept of the flyover was briefed to Administrator Huerta by Congressman Graves 

and summarized in the letter to the Administrator (attachment 1). The letter clearly 

establishes the event as in the Public Interest. The basis of our equivalent level of 

safety is focused on the fact the B-24 has outstanding engine reliability and also has

excellent 3 engine capability for continued flight to suitable recovery bases. The B24 operates with a LHFE exemption (6802) and complies with the required 

maintenance program and crew qualifications/training; the same as the limited 

category aircraft in the exemption. The oversight of the B-24 is focused on safe 

operations with checks and balances managed within the policies and procedures 

established in the CAF Safety Management System.

2. Overview of VE Day Flyover:

WHEN: May 8, 2015 

•WHY: Honor and pay tribute to our nation’s greatest generation on the 70th 

anniversary of VE Day 

•WHERE: Washington, DC and the World War II Memorial through the established 

“Honor Flight” model 

•HOW: Fly historic WWII planes over National Mall 
“THE PLAN” 

•Capitol Mall Flyover 

•Trainers followed by 13 Historically Sequenced Warbird formations and 

concluding with a missing man formation to “taps” 

•Formations in 90-second intervals 

•70+ planes representing the major battles of World War II, from Pearl Harbor to 

the final air offensive to defeat Japan 

HISTORICAL AERIAL REVIEW FLOW 

•Trainer Formation “Pass in Review” (Boeing Stearmans, Piper L-Birds, North 

America T-6s, Cessna/Beech Twin Bomber Trainers

•Pearl Harbor/Flying Tigers (Curtis P-40 Warhawks) 

•Doolittle Raid (North American B-25 Mitchells) 

•Guadalcanal Campaign (Bell P-63/P-39 Kingcobras/Aerocobras) 

•Battle of Midway (Consolidated PBY Catalina, Grumman F4F/FM-2 Wildcats, 

Douglas SBD Dauntless) 

•Yamamoto Shoot down (Lockheed P-38 Lightnings) 

•Ploesti Raid (Consolidated B-24 Liberators) 

•Combined Bomber Offensive—Long-Range Fighter Escort/Tuskegee Airman 

(North American P-51 Mustangs) 

•Big Week (Boeing B-17 Flying Fortress) 

•D-Day (Douglas C-47/R4D Skytrain, Douglas A-26 Invader) 

•Marianas Turkey Shoot/Battle of Leyte Gulf (Grumman TBM Avengers, Grumman 

F6F Wildcats, Grumman F8F Bearcats, Curtis SB2C Helldivers) 

•Battle of the Bulge (Republic P-47 Thunderbolts) 

•Iwo Jima (Vought FG-1D Corsairs) 

•Final Air Offensive to Defeat Japan (Boeing B-29 Superfortress) 

CONCLUDES WITH A MISSING MAN FORMATION TO TAPS 

3. Route of Flight/Restricted Area Waivers

The route of flight and approvals for flight in the restricted areas are being worked 

thru Mr. James Johnson (703) 563-3118 IAW the Administrators’ Letter of 19 

August, 2014 (attachment 2). The interagency suspense’s for these approvals are

very close to the event and history has shown they will not become final until the 

month before the event, or later. However, Mr. Johnson and the General Aviation 

Operations Branch, AFS-830 will be working together as meetings and the process 

continues. 


4. Equivalent Level of Safety:

A. Similar aircraft operation with limited/Standard certificates:

The B-17 and C-47 aircraft are of comparable make, construction, and materials. 

The major reason our B-24 is certificated in the experimental category is because 

the aircraft is configured differently than the original Limited TC issued in 1947 and 

there are no other similar standard category aircraft equivalents. The differences 

and modifications to N24927 with respect to LTC-6-3 issued in 1947 that were 

made to improve operational safety and sustainability. These differences include: 

The original engine configurations listed (R-1830-33, or -67) have been upgraded to 

newer R-1830-75 and -94 engines. The aircraft is operated at lower maximum 

power setting than stated in the 1947 document. The aircraft’s engines are no 

longer equipped with a high speed blower. The CAF has reduced the maximum 

take-off weight of 58,000 pounds to 56,000 pounds so the maximum landing weight 

is never exceeded at any time.

B. Engine Design & Reliability

The B-24 is fitted with four (4) Pratt and Whitney R-1830 power plants. There were 

more of these engines built than any other radial engine and proved to have 

outstanding reliability. These are the same engines used on many of the DC-3 type 

aircraft which are primarily operated in the standard category.
C. Equivalent Level of Safety Questions and Answers

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?

There are no unique or elevated risk factors and safety issues with the LB-30/B24A that would not be found by the operation of any other civilian type of 4 engine 

heavy aircraft. N24927’s in-flight safety record and reliability have proven itself 

and the aircraft will present no elevated hazard for the 70th anniversary overfly. 

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. 

N24927 is a very, very unique example of a B-24 Liberator. Much of her design and 

subsequent operation since 1941 has been civilian orientated verses the combat 

and fast paced war-time training missions of other B-24 models this question 

references. Similar early Liberator aircraft such as the XB-24 and several other B24A models pressed into civilian service as was N24927 lived long successful and 

accident free operational lives until their retirement. In addition, procedural 

improvements, aircraft modernization, an in-depth maintenance program and a 

slow-paced operational environment today verses the 1940’s make this a very safe 

and reliable aircraft. No abnormal or detrimental characteristics exist with this 

aircraft.

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?

No, the CAF Safety Management System provides better guidance for operation of 

the B-24 in peacetime; our regulations are more restrictive and insure the safest 

operations. 
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 R-1830-94 Service Instructions being used? 

Does the CAF uses a QEC unit as an option in addressing engine changes and /or 

malfunctions?

The choice of engines for the early Liberators was the Pratt and Whitney Twin 

Wasp R-1830-33 or -67 S3C4G radial. They were equipped with a two-speed, 

eleven inch diameter impeller supercharger housed inside the aft engine case; 

no turbo-chargers were installed. Early Liberators had round nacelles and not 

the elliptical shaped nacelles of the later mass produced Liberators. The later 

model Liberators operated with upgraded R-1830-43 or -65 engines; this

design changes giving the later models the distinctive elliptical engine 

nacelles were driven by the addition of turbo charging. Liberator Mark II’s 

were equipped with P&W 1830-61 engines with Curtis Electric controlled 

props.

There became a needed to remove the original engines because production of 

the older -33 and equivalent -67 models was halted by the end of WWII due to 

the introduction of upgraded design models. This meant the availability of the 

R-1830-33 and -67 engines steadily declined and future sustainment with this 

particular engine configuration would be difficult and eventually impossible. 

Convair removed the aircraft’s original engines and nacelles and replaced 

them with PBY-5 Catalina units that were still being produced. This is still the 

configuration N24927 carries today.

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?

The current 23E50 Hamilton-Standard Hydromatic Propeller assemblies currently 

being used on N24927 are consistent with the aircraft’s original configuration and 

engine series family. We do not have the resources to account for all military and 

civilian aircraft utilizing this common propeller/engine series equivalent 

combination. However, two prime examples of this successful combination can be 

found in Aircraft Specification No. A-669 for the Douglas DC-3 and TC-2-548 for the 

Consolidated PBY-5 Catalina. Also, the CAF contracts dynamic propeller balancing 

to be conducted on N24927 to ensure safety and reliability. 

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?

N24927 is not equipped with any turbo chargers. Each engine does have an 

integrally driven, single stage, 7.15:1 drive ratio, single speed supercharger. This 
conservative configuration provides ample power to safely operate the aircraft, 

increases reliability and mitigates any hazards. 

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.

There are some differences and modifications to N24927 with respect to LTC-6-3 

issued in 1947 that were made to improve operational safety and sustainability. 

These differences include: The original engine configurations listed (R-1830-33, or 

-67) have been upgraded to newer R-1830-75 and -94 engines. The aircraft is 

operated at lower maximum power setting than stated in the 1947 document. The 

aircraft’s engines are no longer equipped with a high speed blower. The CAF has 

reduced the maximum take-off weight of 58,000 pounds to 56,000 pounds so the 

maximum landing weight is never exceeded at any time.

Also, TCDS LTC-6-3 does not reference a B-24A aircraft; it references this modified 

RLB-30 cargo aircraft. 

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?

Note 1: Detailed Weight & Balance records including equipment listings on DD 

Form 365’s are maintained.

Note 2: Appropriate and required passenger placards are posted in accordance

with current FAR’s and operating limitations. Flight deck speed verses 

configuration limitation warning placards are posted.

Note 3: An updated, yet similar statement made by the issuing FSDO appears in the 

aircraft’s operating limitations.

Note 4: The aircraft is no longer operated in the Limited category as referenced in 

this note and therefor the 337 documentation system does not and cannot apply. 

Detailed records of any repairs or modifications are kept in the aircraft logs.

Note 5: This note no longer applies because this aircraft is no not operated for 

night flying as stated in and restricted by its current operating limitations. 

9. Since over time Consolidated improved upon many of the deficiencies of the early B24s (LB-30/RAF Liberator I & II, B-24A-D) as it developed later versions (e.g., J and H), 

what risks may have been re-introduced by the CAF into N24927 by converting it back to 

a stock “A” model? If so, how are they mitigated?

The reconfiguration of N24927 back to a B-24A model appearance was a cosmetic 

conversion, not a structural change, major modification, or regression in safety. No 

part of this project re-introduced any hazard or risk into the operation of this 

aircraft. Even the hatches and windows reinstalled in the aircraft involved 

uncovering skinned-over cover panels of pre-existing openings; not fuselage 

structure modifications. Listed below are a summary of the changes made during 

the B-24A model reconfiguration:

 Replaced nose greenhouse glass
 Installed bombsite & bombardier furnishings

 Reconfigured nose gun assembly

 Relocated and installed new pitot tube assemblies

 Reconfigured flight deck instruments

 Refinished flight deck furnishings

 Installed 4 each flight deck overhead windows

 Installed flight engineer hatch window

 Removed flight deck cabinet and installed navigator’s seat

 Installed interior lighting system

 Removed storage bins and wooden cargo floor

 Installed 4 passenger seats in forward bomb bay

 Installed forward and aft bomb racks (non-structural)

 Replaced and relocated fuel sump drain lines

 Installed bomb bay walkway

 Radio compartment floor installed in correct location

 Troop seats installed in radio compartment

 4 each radio compartment windows installed

 Auxiliary battery installed in above wing area

 Original top gunner side floors installed w/ storage area underneath

 Aft fuselage interior walkway ladder installed

 2 each top gunner windows installed

 Side hinged cargo door reconfigured to drop-down style

 Functional RH waist gunner hatch and gun mount assembly installed

 Waist gunner flooring installed w/ storage underneath

 Tunnel gun station/hatch assembly installed

 4 each tunnel gun windows installed 

 Fuselage gun storage provisions installed

 Functional tail gunner position, doors, and furnishings installed

 2 each aft tail gunner windows installed

 2 each upper tail gunner windows installed

 Pogo assembly rebuilt and modified to telescope

 Elevator assemblies recovered

 Rudder assemblies recovered

 Aircraft exterior painted in camouflage pattern w/ “Ol 927” nose art 

applied

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?

NLG collapses did occur on many B-24 aircraft during wartime operations, but 

this scenario was more common in the D & J models. Much of this was due to 

the much heavier weights and austere airfields they were operating out of 

which proved to be too much for the MLG design. In addition, the aircraft were 

equipped with what proved to be a sometimes inadequate NLG shimmy 

dampener system. The NLG shimmy damper was eventually upgraded to a 

much more effective later designed unit as opposed to the dual configuration 

originally installed. N24927 is equipped with the newer, improved design. In 

reference to the May 26, 2012 NLG incident several improvements and 

procedural controls have been implemented to mitigate any such 

reoccurrence. The incident came about due to a hydraulic system failure that 

did not fully lock the NLG in the down position. The failure point of the 

hydraulic system was upgraded, additional personal protective equipment 

was installed on the aircraft to better handle any such scenario, procedural 

changes were made to physically verify the NLG is down and locked each gear 

cycle and the use of an additional NLG down lock tool is installed. 

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.

N24927 is equipped with a very much simplified mechanical version of one of the 

two early B-24A fuel transfer systems. The system utilized 4 each mechanical 

valves that correspond to each engine that provide varying sources of fuel supply 

to any engine from either tank, with any of the 4 electric boost pumps, or provide a 

fuel supply to any engine driven fuel pump as needed; the system is unlimited in 

transfer capabilities. This aircraft does not have the complicated fuel bladder 

configuration and hydraulic pump transfer system utilized on other versions of the 

B-24 (early or late models). The fuel tank and transfer system on this aircraft has 

been simplified and is no longer problematic or pose any fire potential.

The only potentially possible ignition source associated with the fuel system is the 

electric boost pumps. This hazard is mitigated by pump design and flight crew 

awareness/system pre-flight inspection training. Each pump is equipped with a 

case drain section that will catch and drain any fuel that could potentially bypasses 

the Garlock seal and enter the electric motor thereby eliminating any fire hazard. 

Inspecting these case drains is a specific pre-flight checklist item to ensure safety of 

flight. In the event of any fuel vapor build-up in the bomb bay area, the aircraft is 

equipped with ram air ventilation on both sides of the fuselage just forward of the 

fuel tanks and 4 side windows to eliminate the hazard. 

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?

The aircraft is equipped with a left and right main fuel tank that extend from the 

wing center section outward to the inboard side of the #2 and #3 engines . Each of 

these is a wet tank containing no bladders each with a 1,500 gallon capability. The 

aircraft does have any auxiliary fuel tanks or any kind. 

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?

N24927 never saw service with the USAAC/USAAF. Though it was delivered to the 

British Air Ministry in May, 1941 the aircraft was returned to Consolidated in July 

1941. It served throughout the war and two years afterwards in company service. 

Records kept of all modifications and TCTO’s were internal Convair company 

documents. The airworthiness and updates of the aircraft was validated by the 

CAA in 1947 and the aircraft entered official civilian service. 

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 checklike? Any leftover processes (non USAAF) from its time under Mexican Registry?

The available military technical guidance does vary from the AIP in regard to 

airframe and engines and sub systems, but not so much in overall aircraft 

structure. N24927 was never equipped or configured with engines, systems, 

components and furnishings like the later model B-24D and J models so a majority 

of that technical data referencing inspection items and life-limited parts is nonapplicable to this aircraft. The criteria and process laid-out in the current AAIP 

established in May 19, 1992 has proven to be adequate in maintaining the safety 

and reliability of this aircraft. 

N24927’s AIP is not on a progressive schedule; it is based on an hourly/calendar 

schedule. The “A” Continued Service Inspection is accomplished anytime the 

aircraft has not been operated in 30 continuous days. A “C” Inspection is 

accomplished on the aircraft, engines and propellers every 50 hours. A “D” check is 

accomplished every 100 hours of flight time and/or annually regardless of flight 

hours accumulated if the 100 hour mark has not been reached. Special inspections 

such as hard landings and lightning strikes are accomplished on an “as needed” 

basis.

There are no leftover unique processes that are required or accomplished from 

this aircraft’s service life with Continental Can Company or its time in Mexico. 

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?

AD 2003-18-01 has been complied with. In addition, an exterior visual inspection 

of the referenced area and the front wing spar, front spar web and lower skin of the 

wings from the center wing station outward to the engines on both sides of the 

aircraft are accomplished during each annual maintenance inspection. To date, no 

discrepancies or structural anomalies have been discovered. 

16. What other ADs, SBS, or other civil requirement/guidance applicable to the LB-30/B24A have been considered and incorporated? 

No other LB-30/B-24/C-87 specific ADs, SBS, or other civil guidance beyond current 

FAR’s, the aircraft’s operating limitations, AAIP and technical data is available.

17. What ADs, SBS, or other civil requirement/guidance applicable to the R-1830, the 

Hamilton-Standard 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?

In regard to the Hamilton-Standard propellers, AD 81-13-06 Rev 2 is complied with 

every 5 years on each propeller assembly. This AD was last complied with on all 4 

assemblies on April 11, 2012. Also, AD 64-03-03 for solid foreign object damage is 

complied with on an “as required” basis. In regard to the R-1830 engines, we 

outsource major engine repairs and overhauls and rely on the subject matter 

experts to track and accomplish all AD and SBS; associated documentation if kept 

on file. The CAF’s B-24 maintenance program does accomplish AD 56-06-02 for 

cylinder flange attaching studs during the annual maintenance inspection, as well 

as, during any engine cylinder changes. 

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? 

Since the B-24A reconfiguration of N24927 there have been no other flight 

emergencies, in-flight failures, or in-flight engine shutdowns besides the NLG 

collapse referenced earlier in question #10. The only other significant issue since 

the reconfiguration was a precautionary removal of the #3 engine for abnormally 

high oil consumption. Occasional minor non-safety of flight and/or non-mission 

limiting discrepancies will occur and are corrected by the appropriately A&P 

licensed flight engineer, or other CAF maintenance personnel. Detailed records of 

these minor discrepancies are listed in the aircraft maintenance log.

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

N24927 is not equipped with an automated fire detection system. Fire detection is 

performed by the flight engineer and loadmaster/scanner. The Halon 1301 fire 

suppression system is fully operational and inspected during the aircraft’s annual 

maintenance inspection. The serviceability of the fire suppression system is 

verified during each pre-flight inspection by the flight engineer. 
20. What is the SOAP (Spectrometric Oil Analysis Program) frequency and results since 

September 2010?

SOAP samples have been and continue to be taken every 50 hours of in-service 

time on each engine. To date, the results have revealed no discrepancies, or 

negative trends. SOAP samples will continue to be taken on this schedule and 

the results tracked throughout the life of each engine.

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

Aging aircraft and corrosion control issues are a large part of the CAF’s B-24

sustainment program. During the annual maintenance inspection, in-depth 

inspections of the wings, tail structures and lower fuselage are performed 

including non-destructive inspections of spar, primary structural components and 

attachment points. Aircraft secondary structures and surface skins also undergo 

corrosion inspections. Regular lubrication and corrosion preventative treatments 

are made, as well as, touch up painting whenever or where ever necessary. 

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?

Without first-hand experience of the wing spar repair made to N224J or a copy of 

Report No. CF-B4J-44052-001SA referencing the splice no comparison can be made 

to N24927. No safety of flight defects were found on N24927’s wing spar during the 

accomplishment of AD 2003-18-01. As a precaution and to ensure long-term 

sustainability, safety and operation of this aircraft for future generations, 

engineering was consulted and a reinforcement doubler was installed on the 

forward wing spar. 

23. What are the configurations and redundancies installed in the aircraft? What nonstandard additions were incorporated that enhance safety?

Numerous redundancies and back-up systems are built into this LB-30/B-24A

aircraft. Today, the aircraft is operated at a much lower weight and power 

settings than its original combat design; this greatly increases the safety 

margin and performance aspects of the aircraft. Its configuration has also 

been simplified to increase safety by the removal of such systems as oxygen, 

auxiliary heaters, galley, lavatory and interior luxuries. The proven Liberator 

design and light operational weight make this aircraft safe and reliable. 

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?

It is very true that due to the lightly skinned and flexible 4 bomb bay doors and 

single keel beam design, all actual bomber versions of the B-24/LB-30 had very 

poor ditching/crash landing survivability. However, variants of the aircraft such as

the C-87, RB-24 and RLB-30 (such as N24927) aircraft did not share this 
characteristic because the bomb bay door and keel structure was removed and 

replaced with an enclosed, fully supported solid structure and cargo floor. This 

maximizes ditching/crash landing survivability. 

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.

There have been no instances of tail vibration, flight control surface deformation or 

control cable failures on N24927. The CAF’s B-24 is a much cleaner and lighter 

version than that of the B-24J model. Consolidated also made many improvements 

to N24927 during its test time and operational service use with the company. In 

addition to the improved RY-3 fuselage nose section and NLG improvements the 

original tail section was replaced with an empennage assembly rated to 18 G’s. The 

CAF does restrict N24927’s maximum speed, but it is not due to structural failure

reasons. There are many varying speed limitations posted in early LB-30A, LB-30B 

and B-24A technical data & the LTC, the CAF has reduced N24927’s Vne at 

41,000lbs to 305 knots and Vne at 56,000 lbs to 235 knots. These restrictions are 

made solely to enhance operational safety and preservation by eliminating any 

wear and tear on the airframe and engines brought about by unnecessary high 

speed operations. 

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” B-24s, and in fact the nose extension in later models 

was primarily to help, but not resolve, this CG issue. 

Though N24927 was originally an LB-30B/B-24A short nosed Liberator 

Convair upgraded the aircraft with the long Liberator nose from a RY-3 

aircraft. All Liberators have had an extremely narrow center of gravity and 

Diamond Lil’ is no exception. The center of gravity on this large 67’ long 

aircraft is only 11’’. Loading of this aircraft is extremely critical on the ground 

to prevent her from falling back on her tail and maintaining her designed 

flight characteristics in the air. Each and every restoration, reconfiguration or 

repair project is heavily scrutinized within the very detailed CAF weight and 

balance program. Most impressive is the fact, that after all of her numerous 

configuration changes throughout her life that she still maintains her original 

center of gravity line at 311.5”. A detailed weight and balance calculation is 

accomplished by the flight engineer prior to every operation of N24927 to 

ensure the aircraft is within the CG limits.
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.

The crew will be 6802 qualified and the pilot will be FAST qualified. The crew 

assignments will not be done until we get closer to the event and all crew 

information will be submitted with additional information required by secret 

service and tsa about 60 days prior.

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?

N24927 does carry a flight engineer as a required crew member position, but the 

Operating Limitations do not require FAA licensing, or currency requirements 

beyond that of internal CAF procedures. The FE position does not touch any 

primary or secondary flight controls or engine controls. This position is probably 

better described as a flight mechanic. Qualified CAF B-24 flight engineers must 

meet minimum time requirements, attend the required CAF FE ground school 

course, perform OJT on servicing tasks/inspections/normal and emergency 

procedures, 6 (minimum) training flights and pass an in-depth final check. 

Currency requirements involve an annual check ride. Some facets of USAAC/USAAF 

B-24 FE training is adhered to in regard to system operation and emergency 

procedures should they be necessary.

29. What ground crew and grounds support is used? What special pre-flight and postflight inspections can be performed to enhance safety?

No additional ground support beyond the flight crew and the equipment 

carried aboard N24927 is necessary to sustain normal aircraft operations. 

The pre-flight and post-flight inspections performed by the flight engineer 

each and every time the aircraft is operated encompass a very in-depth, 

serious and detailed safety and serviceability inspection of the aircraft. The 

mechanical condition, proper servicing, safety equipment condition, loading

security, weight & balance calculations and dropped object prevention are 

incorporated into each of these inspections prior to flight. 

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

Parts acquisition and spares serviceability are all controlled by and solely the 

responsibility of the B-29/B-24 Squadron’s head Crew Chief. This ensures a 

specific focal point of high level of experienced quality control and vendor 

oversight. 

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

impact the operation of N24927.

Yes we have a SMS program submitted as an attachment to the B-29 exemption 

request and CRM is a module in our annual 6802 ground school.
32. On the issue of engine/powerplant and propeller failure and related issues, please 

provide the mitigating strategies for the following: 

 Engine Failure & Fire;

Courses of actions for these scenarios are detailed in the flight 

manual and emergency checklist

 Putt-Putt Fire & Containment;

 This aircraft is not equipped with an auxiliary power unit (puttputt)

 Propeller Overspeed and Separation;

Course of action for this scenario is detailed in the flight manual

 Hydraulic & Electrical Failures;

Alternate methods of energizing these systems and back-up subsystems are available and detailed in the aircraft flight manual. 

These actions are accomplished by the FE 

 MEL & Flight Abort Criteria;

 The PIC makes the decision about aborting/diverting/making 

precautionary or emergency landings based upon the malfunction and 

environmental conditions when an inflight malfunction occurs. There is no way to 

establish criteria for all possibilities and this is true in every flight operation, 

regardless of aircraft category.

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

proposed overflight? Please provide details.

The coordination with all appropriate agencies is being done thru Mr. Johnson as 

directed by the Administrator. AFS-800 has been invited to the teleconferences and 

the meetings. 

Mr. James JJ Johnston 

Manager, National Capital Region Coordination Center 

FAA System Operations Security 

National Tactical Security Operations

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

detail on the following:

The answers to the questions below are discussed in appropriate sections above. 

Additional detail will be available after the required coordination with other 

agencies managed thru Mr. Johnson and AFS-800 will be actively involved in 

working out the details for maximum safety.



 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 B24J, 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

 

5. Risk Mitigation and Assessment:

The answers to the questions above touch on specific risk and mitigations requested 

by AFS-830. However and in general terms, this assessment addresses events which 

pose a danger to people and structures on the ground. The scores are listed here and 

the risks are shown in the Matrix. None of the risks are in the caution or danger 

zones.

1. There is no history with the B-24 which shows catastrophic failures resulting in 

immediate loss of aircraft control. Assessment: improbable/catastrophic

2. The most significant failure would be an engine fire and a simultaneous failure 

of the fire suppression system, or a fire in a component located in an area where 

the crew would be unable to fight the fire with onboard suppression systems. 

The immediate action in either case would be an immediate diversion to the 

closest diversion field, which during the flyover would only take 3-5 minutes 

and is within the window for a safe recovery. Assessment: remote/negligible 

3. Engine failures without fire, or fires successfully suppressed are managed by 

shutting down the engine and proceeding to a suitable airport. Three engine 

performance is sufficient for maintaining altitude and airspeed and normal 

procedures are followed for flight to the suitable airport. 

Assessment: occasional/negligible 

4. The possibility of two engines failing is extremely remote; however, two engine 

performance at the operating weight for the flyover, and other local flights, is 

sufficient for continued flight to the diversion airports along the route of flight 

during the flyover and can be accomplished with a positive rate of climb at the 

planned altitude. Assessment: remote/negligible

5. The possibility of a midair collision within a formation is mitigated by managing 

the qualifications of the pilots and the flight profiles. The pilots flying formation 
will be qualified IAW FAST standards and the flight profiles are straight and 

level point to point. Furthermore, midair collisions within a formation rarely 

result in loss of control, or major aircraft damage. Midair collisions within 

formations which result in loss of control are primarily in high “G” or highly 

maneuvering elements. Assessment: remote/marginal

 (CONTINUED ON NEXT PAGE)
Risk Assessment Matrix

Population/Structures in DC Area for VE Day Flyover

Severity

Likelihood Negligible 

IV

Less than

minor injury 

and/or less 

than minor 

structure

damage

Marginal

III

Minor injury 

and/or minor 

structure

damage

Critical

II

Severe injury 

and/or major 

structure

damage

Catastrophic

I

Results in 

fatalities 

and/or loss 

of structures

Frequent = A

Continuously 

experienced

Probable = B

Will occur often

Occasional = C

Likely to occur 

sometime

Engine failure

Remote = D

Unlikely, but 

possible

Uncontrolled 

fire/two 

engine failure

Midair

Improbable = E

So unlikely, it can 

be assumed it will 

not occur

Loss of 

control

 (CONTINUED ON NEXT PAGE)
6. Summary:

Participation of the B-24 in the flyover of the National Mall celebrating the 70th

anniversary of the end of WW II is in the public interest and the safety of the 

population is equivalent to previously approved flyovers with similar routes in the 

Washington DC area. I look forward to the opportunity to work with the Agency 

answering questions as they arise during the staffing of our request. Please contact 

me on my cell, or via email should the need arise.

Sincerely,

Robert A. Stenevik

Vice President of Safety, Maintenance and Operations

Commemorative Air Force

Cell 817-705-5817

rstenevik@cafhq.org

3 Attachments:

- Congressional Letter to the Administrator

- Administrators’ Letter of 19 August, 2014

- CAF Safety Management System Guide